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Jewish and Islamic Law, A Comparative Review


The Relationship between Jewish and Islamic Law

Comparative studies in the field of Jewish and Islamic Law began more than 150 years ago with the publication of Abraham Geiger's Was hat Mohammed aus dem Judenthum aufgenommen (1833, rev. 1902). That study, and those that followed, concentrated primarily on the attempt to pinpoint cases in which Jewish law influenced Islamic law in the latter's early stages, against the background of the close physical and geographical proximity of Jews, Arabs, and Muslims – sometimes as actual neighbors – around the time of Islam's birth and later, creating what scholars have called "a state of symbiosis." Scholars were also mindful of the overall similarity of the two legal systems, both being casuistic, formal, personal, relevant to all areas of human behavior, developed mainly by the efforts of legal scholars rather than by judicial precedent; both do not distinguish between state and religion, since both give religious law precedence over the state; both distinguish between areas associated with religious ritual (issur ve-hetter in Judaism, 'ibādāt) and those relating to private law (dinei mamonot, mu'āmalāt), between matters concerning man and God (bein adam la-makom, ḥaqq Allāh) and matters concerning interpersonal relations (bein adam la-ḥavero, ḥaqq ādamī). In both systems, a system of punishment evolved alongside that prescribed by the Bible (rabbinically ordained flogging) or by the Qur'ān (Koran; ta'zīr punishments based on the late principle of siyāsa shar'iyya – administrative justice within the limits of the Shari'a).

Despite the similarities in the main characteristics of the two legal systems, the differences are clearly visible. Thus, although both were developed by legal scholars, the Muslim magistrate, the qāḍḍī, generally appointed by the ruler, is not necessarily well versed in the law but must consult with legal scholars, his main task being the administration of the law in practice; neither can his judgment be appealed in a higher court. In Jewish law, however, the court generally comprises several judges (3, 23, or 71) who must be learned in the law; litigants often having the option of appealing to a higher court.

Quite naturally, early comparative studies of Jewish and Islamic law focused mainly on the influence of Jewish law in ritual matters ('ibādāt), such as prayer, fasting, charity, ritual fitness of foods, etc., and less on other areas of law. In time, particularly in recent years, attention has also focused on the influence of Islamic law on Jewish law. Any discussion of the relationship between the two systems must therefore concern itself with two phases: (1) the early history of Islam, characterized mainly by Jewish influence on Islamic law; and (2) greater influence of Islamic on Jewish law as Islam consolidated its political power and evolved its own legal principles, from the 8th to the 12th centuries. Muslim influence, however, never actually reached the proportions of "legal transplants," but was rather limited, primarily affecting a few topics of legal theory, private law (mu'āmalāt), and, to a certain degree, genres of legal literature.

The comparative study of Jewish and Islamic law is meaningful not only in areas of mutual influence, but also as regards differences and parallels owing to social and economic factors (representing the human age in their background), to the possible influence on both of a third legal system, or to early traditions in the environment in which each evolved (the so-called "juristic koiné"). A major object of study is thus the characterization of each system and its particular trends of development. In the following discussion, the specific characteristics of each system and the relationship between the two systems in both phases will be reviewed, as well as parallels that were not necessarily the result of mutual influence.

first phase

The earliest evidence in the first phase is of local Jewish customs that influenced the Arabs in pre-Islamic times, as attested by various Arab traditions, such as ablution before prayer: "For we have Jewish neighbors and they are accustomed to wash their lower parts of excreta, and we washed as they did" (Kister, "On the Jews of Arabia," p. 231). These traditions persisted after the birth of Islam: "'We washed with water during the jāhiliyya and did not abandon [the practice] when Islam appeared,' he [Muḥammad] said, 'do not abandon it'" (Kister, ibid.). Such influence finds expression in the Qur'ān, which in several cases notes that it is sometimes guided by earlier books or laws (as in iv, 31; v, 52; etc.). Some sūras in the Qur'ān clearly echo biblical or mishnaic texts. For example, v, 45 reads: "And therein [= in the Torah] We prescribed for them: 'A life for a life, an eye for an eye, a nose for a nose, an ear for an ear, a tooth for a tooth, and for wounds retaliation'; but whosoever forgoes it as a freewill offering, that shall be for him an expiation." This is a close parallel of the biblical verses Ex. 21, 23–24 and Deut. 19, 21. Another example (ibid., 32) is: "Therefore We prescribed for the Children of Israel that whoso slays a soul not to retaliate for a soul slain, nor for corruption done in the land, shall be as if he had slain mankind altogether; and whoso gives life to a soul, shall be as if he had given life to mankind altogether," echoing the well-known mishnaic adage "Whosoever destroys a single soul of Israel, Scripture imputes [guilt] to him as though he had destroyed a complete world; and whosoever preserves a single soul of Israel, Scripture ascribes [merit] to him as though he had preserved a complete world" (San. 4, 5). The verse prescribing the beginning of the fast of Ramadan (ii, 187), "Eat and drink, until the white thread shows clearly to you from the black thread at the dawn…," recalls the definition of the earliest time for reciting the Shema' in the Mishnah (Berakhot 1.2): "From what time may one recite the Shema' in the morning? From the time that one can distinguish between blue and white. R. Eliezer says: Between blue and green." There is also evidence in the Qur'ān, albeit not explicit, for a link between the Muslim fast of Ramadan and the Jewish Day of Atonement: "O believers, prescribed for you is the Fast, even as it was prescribed for those that were before you" (ii, 183). Muslim tradition refers to an indirect link between the Muslim Friday (lxii, 9) and the Jewish Sabbath; it was this link that inspired the people of Medina to request Friday as a day of prayer, when they complained: "The Jews have a day on which, once in seven days, they gather together, and the Christians similarly. Let us establish a day in which we will congregate, speak of Allah, pray, and thank Him" (Kister, ibid., p. 245). It has been argued that some of the Ten Commandments are represented in the Qur'ān, though in Muslim guise. The list of marriages that are prohibited because of a blood relationship (iv, 22) is largely parallel to the list in Lev. 18: 6–20. Some scholars believe that the prohibition of usury in the Qur'ān (ii, 287–288; iv, 33) was also influenced by the Jewish prohibition (Lev. 25:36; Deut. 23:20–21).

It is evident from these examples that the early Muslims were acquainted with Jewish sources not only by observation of their Jewish neighbors, but also, and perhaps primarily, thanks to Jews who had converted to Islam and brought their Jewish traditions with them. This was at first an oral process, with such converts presumably reading the Torah and translating it; the earliest documented Arabic translations of the Torah, however, date to a later period. An early collection of Muslim ḥadīths (al-Bukhari's Ṣaḥīḥ) reports that the Jews used to read the Torah in Hebrew and translate or interpret it for Muslims in their own language. Another tradition relates that Muhammad permitted his followers to read the Torah and tell stories of the Children of Israel from Jewish sources, provided that they did not obey its commandments (Kister, Ḥaddīthū, p. 234). According to one tradition, Muḥammad actually judged Jews who had been accused of adultery, sentencing them to be stoned after he had consulted the Torah itself to determine their punishment; Muslim tradition has it that as a result a verse prescribing stoning, not originally in the Qur'ān, was revealed (J. Burton, The Sources of Islamic Law, 1990, pp. 129–132).

Because of the eclectic nature of the Qur'ān, some Qur'ānic verses, among other things (see below), actually contradict biblical or talmudic law. One example is the prohibition on marriage with one's niece (iv, 22), which talmudic law permits and in fact considers a meritorious act (Tosefta, Kid. 1. 5; Yev. 62b). Similarly, divorce as prescribed in the Qur'ān deviates in two respects from biblical law. First, divorce is effected, according to the Bible, by means of a document handed to the woman (Deut. 24:1–4), whereas a Muslim may divorce his wife by a unilateral announcement; second, the Qur'ān permits a divorced woman who has remarried to return to her first husband (ii, 230), while biblical law forbids such a marriage (Deut. ibid.). There are also differences in inheritance laws: The Qur'ān allows female relatives to bequeath property or inherit it (ii, 7–12), whereas biblical law gives preferential treatment to men in the context of inheritance (Num. 36:1–4). In addition, there are differences pertaining to marriage, dowry, and procedure.

Besides the aforesaid eclectic nature of the Qur'ān, some of the differences between Jewish and Islamic law may also be attributed to the early Muslims' contact with sectarian Jews, who rejected rabbinic halakhah, such as the prohibition of marriage with one's niece. Other differences stem from the particular social and economic structure of Jewish society, which was largely agricultural, as against Muslim society, which was primarily mercantile. These differences might explain the nature of Jewish inheritance law, which tended to preserve the integrity of large properties, whereas Islamic law permitted the distribution of small shares to several heirs. Similarly, Jewish law, characteristically for an agricultural society, impeded the transfer of property by requiring an act of acquisition, whereas the largely mercantile Muslim society was content with oral agreements, which imposed fewer restrictions on commercial life. Some of the differences may be attributed to Muḥammad's tendency to distance himself from the more rigorous aspects of Jewish law, as implied in the Qur'ān (ii, 286): "Our Lord, do Thou not burden us beyond what we have the strength to bear." This tendency was implicit in a later interpretive principle of Islamic law known as rikhsa (permission, alleviation), as against Jewish law, which, as Goitein pointed out in a well-known article, is referred to as azīma (stern, rigid).

Muslim jurists differed as to the status of provisions of Jewish law incorporated in the Qur'ān and in the Sunna. In one view, pre-Islamic law was an integral part of the Islamic system unless explicitly abrogated. This was the case with respect to various laws derived from Qur'ānic verses that had originated in the Bible, such as the verse concerning suretyship (xii, 71–78), of which the Ḥanafi jurist Sarakhsī (d. 1099) wrote: "The law that preceded us is our law as long as it has not been abrogated." Muslim jurists also applied the principle in the areas of dowry and hiring. Other Muslim scholars, however, preferring to distance themselves from Jewish influence, entirely rejected the possibility of Islamic law assimilating laws from the Jewish system.

second phase

The second phase, comprising the period of the geonim (8th to 11th centuries), was marked by a change in the patterns of influence, in that it was primarily Islamic law that began to influence the practice of Jewish law in the Jewish communities of the East; the latter, as a minority group, were influenced by legal practice as determined by the ruling majority, in several areas: legal theory, rules of inference, linguistic terminology, and literary creation. Patterns of Muslim legal literature also influenced the writings of leading Jewish legal authorities. Muslim influence was not without its effect on the lower echelons of Jewish society, which sometimes adopted customs from the environment that reflected Islamic law.

Several factors combined to influence patterns of influence in the second phase. First, the geonim were familiar with Islam and its law, which often provided the background to their own rulings. For example, one geonic responsum, discussing the question of whether a convert forfeits inheritance rights, writes: "…these Muslims… for in the religion of Ishmael they do not permit a convert to inherit the property of his father." R. Saadiah Gaon is familiar with the legal terms relating to Muslim deeds: "I would like to know, concerning a scribe among the Muslims who knows ten formulations from the books of deeds by heart, what would his position be among them? Would he thereby become a sage, or a legal scholar, or a jurist, or a judge?" (all terms taken from Islamic law). In connection with the administration of oaths, R. Hai Gaon rules "that the oath sworn by the Ishmaelites, saying, 'There is no God but Allah,' is a major oath." Elsewhere, he notes: "Thus we see that in this city in which we now live, that is, Baghdad, the non-Jewish courts admit evidence only from competent witnesses, adult and rich, of whom there has been no breath of theft, falsehood or vanity, who are specified in their religion and called al-mu'addilīn." Islamic law is sometimes reflected in the formulation of questions, as in the case when Rav Natronai of Sura was asked: "In our locality it is customary that if a person frees his slave and that slave dies without sons, then his master inherits him" – as in Islamic law, where a master can inherit from a slave. On the other hand, one also finds negative reactions to Islamic law. Thus, R. Yehudai Gaon expresses disapproval of the practice of handing down a legal opinion to one of the litigants: "It is forbidden to discuss the law with him or tell him anything about the law. For that is the practice of the courts of the Cutheans [= non-Jews], that one requests a legal opinion in advance." And Rav Hai criticizes the Muslim version of the lunar calendar, whose festivals do not occur in the same season every year: "…[the Muslims' festivals] move around [from season to season], for their months are the months of the [lunar] year and they have no intercalation."

Another factor that figured in the flow of influence was the frequency of Jewish contact with Muslims and with the Muslim authorities, fear of which inspired the geonim to adopt a generally moderate attitude to Muslim religion, Islamic law, Muslim rulers, and their subjects. The geonim applied the principle of dina de-malkhuta dina ("the law of the state [lit.: kingdom] is law"), on the assumption that Muslim rule was a result of divine providence. Jewish legal authorities therefore acquiesced in the laws promulgated by the Muslim authorities, recognizing deeds issued or approved by Muslim courts, although explicit mention of dina de-malkhuta is fairly rare; their attitude to the Muslim authorities was generally positive: "These Muslims are most solicitous for us and most protective toward us." This may be an appreciation of their judicial autonomy under Muslim rule. However, they also complain of "a cruel and harsh government," implying apprehension of the ruling authorities and the need to make allowance for the imposition of Islamic law in certain areas, as in their ruling that it is permissible administer an oath to a non-Jewish partner, contrary to talmudic law (Sanh. 63b). Because of the prohibition of usury in Islamic law, Rav Hai prohibits loans at interest to Muslims, although the biblical injunction against usury does not apply to non-Jews: "It is not permitted to charge a non-Jew interest save in the case of non-Jews for whom this is proper; that is, who themselves lend and borrow at interest. But as for these Ishmaelites, who forbid this in their religion, it is forbidden to lend them at interest – even learned scholars, for that would involve desecration of God's name." Significantly, they do not consider Muslim wine as "libated wine," not categorizing Muslims as idolaters. There are many other cases of similar import.

A third factor influencing the absorption of Muslim usages was the lenience of Islamic law in certain areas, in regard to both substance and procedure, compared to the corresponding provisions of Jewish law – especially since Muslim courts possessed powers of coercion. Accordingly, there was a growing tendency among Jews to turn to Muslim courts, furthering an appreciation among Jews of the Muslim court system and its regulations. There is ample evidence, for example, of women in the category known as "rebellious wife" (ishah moredet) appealing to Muslim courts in order to circumvent Jewish law, which would not readily grant them a divorce; in such cases the geonim felt it necessary to deviate from talmudic law, in order to keep such women in the frame of Jewish courts.

A fourth factor furthering Muslim influence was the occasional encouragement of Jews to have recourse to Muslim courts, in the hope that such Jews might be persuaded to convert to Islam. This was done in two mutually complementary ways. First was the ruling in most areas of civil law, sometimes also in connection with personal status, such as marriage money, that there should be no difference in the treatment of Muslims and members of the "protected peoples" (dhimmi), including Jews; second, most Muslim jurists ruled that Islamic law would apply even in cases in which only one litigant had appealed to the court.

The above factors explain several innovatory halakhic rulings of the geonic period, as well as the assimilation of various Muslim legal norms in the legal literature, sometimes through the instrument of custom, at other times almost secretively, without any special indication. Customs taken over by the geonim from Muslim practice without change may be called "borrowed" customs, whereas others, constituting only a response to Muslim norms but not necessarily imitating them, may be termed "responsive" customs. Some adopted customs were intended to prevent recourse to Muslim courts, reflecting the fear of the geonim that the more lenient Islamic law might encourage conversion to Islam. Thus, the geonim created a takkanah (enactment) that a "rebellious wife" could obtain a divorce immediately, rather than wait the extensive time required by rabbinic law, without forfeiting the statutory value of her ketubbah (marriage contract). Recognition was accorded to the institution of "estimated" mahr (marriage money), according to which a woman who had lost her ketubbah was entitled to a sum of money as befitted a woman of her position, based on criteria taken from Islamic law. In connection with bankruptcy, they established various procedures at variance with talmudic law: they instituted a new oath of destitution, "I have no means," as practiced in Islamic law (yamīn al-adam); pronounced a ban on recalcitrant debtors as a substitute for the Muslim measure of imprisonment for debt; made arrangements for the needs of a debtor's wife and children when his property was taken over, as was customary in Islamic law but contrary to the ruling of the Talmud. Similarly, we find instances of the geonim permitting husbands to give their adult daughters in marriage without the daughters' explicit agreement, as permitted by some schools of Islamic law but contrary to talmudic law; this was done by creating a legal construct that brought the practice in line with the latter. Many examples of Muslim influence may be found in the realm of commercial law, one of the most prominent being the suftaja (bill of exchange; diokni in talmudic phraseology), in relation to which one geonic responsum states: "Our laws, strictly speaking, do not permit the sending of suftaja, since our Sages said, 'It is forbidden to send money by diokni' [tb bk 104b]…. However, since we have seen that people use it, we have begun to sanction it, so that transactions among people should not be voided. So we have agreed to sanction it in accordance with the traders' law, no more and no less."

An example of a "responsive custom" is the institution of the "anonymous ban" (ḥerem setam), which was devised as a substitute for the administration of oaths to litigants during a judicial procedure, when an actual oath was not sanctioned by talmudic law. The geonim thus created a parallel to the Muslim system of oaths, according to which, in cases of doubt, a litigant could be required to take an oath even in the course of a judicial procedure, not only at its end.

A striking feature of geonic assimilation of Islamic practices is the frequent use of accepted custom to that end; in fact, that was preferred over the talmudic principle of dina de-malkhuta, of which (as already mentioned) they made very little use, perhaps out of reluctance to admit the influence of an external source. They used custom, a well-proved legal source of Jewish law, as a kind of signpost indicating what might be an ad hoc measure, a step in the development of Jewish law according to the needs of time and place. Many such customs associated with the constraints of time and place disappeared later, when the constraints were no longer relevant, and were replaced by a return to talmudic law.

However, as stated previously, Islamic law also made its way into geonic halakhah by channels other than custom; only careful examination of Muslim legal literature can reveal the Muslim source, which is not obvious at first sight. Such examination will reveal the Muslim background prominent in monographs written by the geonim on practical legal topics, such as the laws of abutters' rights or the laws of suretyship (which receive only sparse treatment in the Talmud), as well as on family law and matters of personal status.

Thus, there are clear-cut parallels between the "Book of Abutters' Rights" (Kitāb al-shuf 'a) by Rav Ḥofni b. Samuel (d. 1013) and Muslim works, not only in structure, but also in relation to specific laws that the author seems to have borrowed from Islamic law. A few examples, among many, will suffice: conferral of abutters' rights to land acquired by barter; the right of rescission (khiyār); the existence of abutters' rights in voidable sales; division of a property among abutters on the basis of their number rather than their proprietary rights in the abutting property; establishment of a hierarchy among parties with proprietary rights to the property itself (nafs almubay'), parties with various non-proprietary rights pertaining to the property (such as right of way; ḥuqūq al-mubay'), and abutters proper (i.e., owners of adjoining properties; jār al-mulāṢaq); abutters' rights in the sale of a well or spring in another's property; real-estate transactions that do not confer abutters' rights, such as leasing, bailment, borrowing, or endowment. Moreover, the procedure in pleas concerning abutters' rights largely emulates that customary in Muslim courts. It is especially worthy of note that, even where R. Samuel b. Ḥofni adheres to talmudic law, his formulation is in the style of Muslim legal texts.

Similar links may be observed in R. Samuel b. Hofni's treatise on suretyship and hiring (Kitāb al-ḍamān wa'l-kafāla), many of whose provisions, in addition to the structure of the work and its division into chapters, are taken from the parallel Muslim literature or from the prevalent practice of the milieu. Thus, he devotes separate chapters to various types of suretyship. One chapter deals with suretyship for the obligee's person where the surety's only commitment is to bring the debtor to court. Another chapter deals with a surety who is also committed to defraying the debt in case he fails to present the obligee. There are chapters on the case of a surety who defrayed the debt before he himself or the obligee was sued by the principal, and on suretyship for an unknown sum. Sometimes, Muslim usage in matters of suretyship is cited in a geonic responsum rather than in a special treatise, as in a responsum by R. Sherira Gaon on suretyship. Another work parallel to Islamic law in several aspects is R. Samuel b. Ḥofni's treatise on divorce. Rav Hai's great work Mishpetei Shevu'ot is marked in part by echoes of Islamic law, such as making arrangement for the assets of a bankrupt debtor, as well as the oath of destitution, already mentioned previously.

At this point it should be noted that some of the parallels cited above may well reflect the influence of a third legal system from which both Jewish and Islamic law borrowed, or from an earlier legal tradition (juristic koiné). This may indeed be the case in such areas as abutters' rights and suretyship; alternatively, Islamic law may have been merely the channel through which they reached Jewish law. Some of the parallels and similarities may be explained on the basis of S.D. Goitein's theory of feedback or "full circle," according to which an idea was adopted by Islam, transformed and reshaped, and subsequently, in a new guise, "came round full circle" and impacted Jewish law. Examples of this process are the Muslim mahr (marriage money, dowry) and suretyship for person, both already found in biblical law (in the latter case, some Muslim jurists admit this origin). Both institutions experienced further development in Islamic law, finally returning in a new figuration to influence Jewish law.

Links with Islamic law may also be identified in the area of legal theory (uṣūl al-fiqh), especially in the writings of R. Saadiah Gaon and R. Samuel b. Ḥofni. As shown by M. Zucker and later scholars, Muslim writings are the source not only of the metaphorical terminology of "roots" and "branches" (uṣūl, furū') in relation to legal analogy (qiyās), but also of some of the basic conceptions of qiyās and its practical application, especially as formulated in the writings of Saadya and Samuel b. Hofni, who were apparently influenced mainly by Mu'tazila scholars. Such is the case, e.g., in regard to the question of whether analogy produces certain knowledge or only plausibility, or even in regard to the actual use of analogy as a source of law. The first signs of the use of consensus as a source of law in geonic works, including its definition and relationship to tradition, attest to the influence of the Muslim concept of ijmā'. The same is true of the use of interpretive tools taken over from commentaries on the Qur'ān, such as the terms maḥkamāt (univocal expressions) and mutashābāhāt (equivocal expressions), which were employed by both geonim and Muslims, among other resources, to explain contradictory verses in the Bible.

The primary genre of legal literature used by the geonim at this time, the halakhic monograph, dates back to R. Saadya Gaon, continuing in the later period of R. Samuel b. Ḥofni and Rav Hai. These authors' formularies (manuals of deeds, shurūṭ, wathā'iq) and dozens of other works, which later provided the basis for Maimonides' great work of codification, were written along the lines of the Muslim model.

After the geonic period, one finds less frequent instances of the influence of Muslim sources or of responsa written against the background of Islamic law or religious practice. An underpinning of Islamic law may be detected only rarely in the works of R. Joseph ibn Migash or R. Isaac Alfasi, both of whom, used concepts borrowed from the Muslim world, such as substance and accident (jawhar, 'arḍ), in connection with obligations concerning tangibles and intangibles. At times, Alfasi also employs Islamic legal terms, such as naẒar, dalīl, and istidlāl, in his talmudic discourse. Maimonides, however, betrays Islamic influence more frequently in his wording, in legal formulas, in methods of interpretation (tāwīl, ẓāhir, and bāṭtin), and in actual laws and legal institutions; but it is not always possible to determine whether he was influenced directly by Muslim sources and practice or, indirectly, by geonic rulings and terminology, themselves reflecting the influence of Islamic law. Particularly prominent in Maimonides' code are certain provisions in the area of public law, in his "Laws concerning Kings," which reflect Muslim thought and parallel elements of Islamic law. This is especially apparent where he rules, for example, that a Jewish king is not bound by normative penal law and procedure – recalling the Muslim institution of al-naẓar fi'l-mazālim ("investigation of complaints concerning injustice"). In regard to the supervision of public morals, Maimonides' treatment recalls the Muslim institution of muḤtasib. In family law and personal status he employs norms and practices borrowed from Islamic society and law: restrictions on women's freedom of movement, the husband's right to beat a wife who ignores her wifely duties, and so on. In private law (suretyship and abutters' rights) he lists a series of laws which, both in general and in particular, may well have been taken over from the Muslim legal literature. In legal theory he applies some aspects of analogy (qiyās) according to the Muslim model, makes frequent use of consensus (ijmā') both in his code and in the Guide of the Perplexed, and divides human behavior into five "legal qualifications" (aḥkām al-khamsa), a common pattern in Muslim legal literature. The very structure of his code Mishneh Torah resembles in some respects the style of the parallel Muslim literature (fiqh). Maimonides' usage in the area of legal theory and positive law shows at times the influence both of the Shi'a Isma'ili sect and of the Sunni Shafi'i school. These schools were particularly active in Egypt, which was also the locale of Maimonides' halakhic activity, and they most probably contributed to the consolidation of his legal theory. As is well known, Maimonides followed several geonim in ruling that Muslims were not to be considered as idolaters, and this ruling may have influenced his attitude to some of their practices and customs.

Where Islamic law contradicts Jewish law, however, Maimonides will often use rhetorical or polemical tools to reject it. Thus, he rules against imprisoning a debtor who pleads destitution or even against administrating an oath to such a debtor; he stresses the halakhic requirement that divorce be effected by a written document, pointing out the danger of oral divorce as in Islam; he upholds the need for the public nature of the marriage ceremony; and in the area of commerce, he rules that a sale cannot be effected by oral means alone as in Islamic usage.

An acquaintance with Islamic law is also evident in the writings of Maimonides' son Abraham b. Maimon, and its influence may sometimes be detected. In one responsum (Resp. R. Abraham ben ha-Rambam, Jerusalem 1938, #97), he writes that the laws of abutters' rights are also practiced "by people other than our coreligionists," clearly referring to the Muslims. In another (ibid., #66), he employs the phrase "the gate of investigation and analogy is not closed," echoing a dispute among Muslim scholars as to whether the "gates of ijtihād" were closed; and in his Sefer ha-Maspik le-'Ovedei ha-Shem he discusses the relationship between written law, analogy, and custom in terms that recall the Muslim approach: "Custom is not the main thing that should govern our conduct, but written material or analogy, or both together." Abraham b. Maimon is also known to have been influenced by Islam in synagogue procedures, such as ablution, prostration, and seating arrangements, among others.

Later Spanish-rabbinical authorities, such as R. Asher b. Jehiel, R. Solomon b. Adret, R. Simeon b. Ẓemaḥ Duran, and R. Solomon b. Simeon Duran, show only isolated instances of the influence of Islamic law. Such instances may be found in the area of marriage law, such as R. Simeon b. Ẓemaḥ Duran's discussion of polygamy, where he recommends the egalitarian treatment of polygamous wives, or the connection made by R. Simeon b. Ẓemaḥ, R. Isaac bar Sheshet, and R. Solomon b. Simeon Duran between the Jewish ketubbah and the Islamic mahr (ṣadāq). Islamic influence is also felt in the treatment by several authorities of the arrangement for payment of ketubbah money where a woman has lost her ketubbah. Further reference to Islamic law in these sources revolves around the question of the desirable Jewish attitude to Islamic religious customs and to the usage of the Muslim environment, such as the obligation of a witness to take an oath as to the truth of his testimony, cutting the hair, eating flesh of animals slaughtered according to Muslim custom or in the direction of Mecca, taking off one's shoes upon entering the synagogue, hanging a mat with an illustration of the Ka'ba in the synagogue, and other subjects (R. Asher b. Jehiel and others).

Sources of the Law in Jewish and Islamic Tradition

The Sharī'a recognizes four sources: The Qur'ān, Sunna, ijma' (consensus), and qiyās (legal analogy). The first two, Qur'ān and Sunna, are written sources (nass), whereas the last two, ijmā' and qiyās, are unwritten methodological legal sources. Islamic law does not recognize laws of equity or any equivalent of the halakhic principle of lifnim mi-shurat ha-din ("beyond the strict letter of the law"). The principle of istiḥsān (public welfare), which seemingly allows for deviation from legal analogy where necessary for the public good, is not generally perceived as a rule of equity; it has been described by some authorities as a kind of hidden analogy, the basic idea being that the ratio of a legal rule from which inferences are to be made as to a new rule is not immediately obvious. By contrast, Jewish law recognizes a broad spectrum of legal sources, including midrashic exposition, enactment (takkanah), custom, reason (sevara), and precedent. In addition, there are valid rules of equity, such as the aforementioned lifnim mi-shurat ha-din or the rule based on the biblical verse "Do what is right and good" (Deut. 6:18).

Underlying the differences between the sources recognized in each system are their conflicting attitudes to the law in general. Common to the four Muslim sources, as emerges from the legal literature, is the tendency to leave the law and its sources in the province of divine revelation, and to restrict as far as possible – if not absolutely to avoid – human involvement in the development of law and the establishment of legal norms. Thus, the verses of the Qur'ān are not readily interpreted in any sense other than the literal; any law in the Sunna must be supported by a hadīth consisting of the matn, the body of the tradition, and the isnād, a chain of transmitters traced back to Muhammad or his companions and thereby endowed with an indelible prophetic stamp of approval. Consensus (ijmā') is intended mainly to approve (a posteriori) norms upon which Muslims have agreed, such agreement attesting to their truth and divine origin; consensual norms are therefore almost inviolable, although consensus by itself cannot be used to establish future legal norms. The task of analogy (qiyās) is the expansion of existing law from a written source, but never the creation of new legal norms. Other principles accepted by Islamic law as tools to effect legal changes, such as the aforementioned istiḥsān (the principle of public welfare) and ijtihād, "effort," i.e., the use of individual reasoning or exegesis to decide the law, caused no significant change in the theological perception of law as based invariably on a divine source. We have already pointed out that istiḥsān was not seen as a channel of equity but as a kind of hidden analogy. In effect, therefore, Islamic law always remained "in heaven," the sole task of the jurist being to reveal it, with no freedom to exercise discretion in laying down the law.

In Jewish law, by contrast, the recognized sources grant halakhists extensive authority to develop legal creativity, on the basis of the biblical verse "It is not in heaven" [Deut. 30:12], as established in a celebrated dispute between R. Eliezer b. Hyrcanus and the Sages concerning the ritual purity of the "oven of Akhnai" (bm 59b). The difference between Jewish and Islamic law, in consequence of their different theological perceptions of the sources of law and the authority of legal scholars had implications in many areas of the law, determining the specific character of each. Islamic law, lacking suitable tools of jurisprudence, remained basically static, whereas Jewish law, by virtue of its sources of law, was more dynamic and enabled halakhists to cope more easily with changing realities.

These differences can be demonstrated in areas where the original legal nucleus of both systems was the same or similar, but because of the different nature of their legal sources, Islamic law remained relatively static, whereas Jewish law was capable of adapting itself to new conditions. Thus, for example, there was at first no basic difference between the Muslim mahr and the Jewish ketubbah (in the sense of a statutory payment). The biblical mohar (bride-price), originally a matter of oral agreement as to the payment made to the bride's family at the time of the marriage, as was customary in Islamic law, gradually evolved into the written document known as the ketubbah. Rabbinic sources attribute this development to R. Simeon b. Shetah, who "ordained that all the property of a husband is pledged for the ketubbah of his wife" (Ket. 82b); consequently, the payment, instead of being made before marriage, became a debt payable to the wife at a later date in the event of her being divorced or widowed. This revolutionary development created a major gap between the two systems, which might otherwise have remained very similar in this respect.

There are other aspects of divorce laws in which Jewish and Islamic law were at first largely in agreement, but later drew apart owing to the dynamic and adaptive nature of Jewish law. Thus, in Jewish law as represented by the Mishnah (Yev. 14:1), later also accepted by the geonim in Iraq, "While a woman may be divorced of her own free will or against her will, a man can give divorce only of his own free will." Even more extreme was the attitude of R. Akiva, who taught that a husband may divorce his wife virtually at will, "even if he finds another woman more beautiful than she is" (Mishnah, Gitt. 9:10). The divorce procedure, too, is a private affair, with no involvement of the religious court. These aspects also exist in Islamic law as practiced (except for the halakhic requirement that the writ of divorce be handed to the woman, for which there is no parallel in Islamic law, and the biblical prohibition of remarrying one's divorced wife if she herself had remarried in the meantime). Jewish law, however, as practiced by Ashkenazic Jews, was radically altered by an enactment, attributed to R. Gershom Me'or ha-Golah (Germany, 11th century), forbidding a husband to divorce his wife against her will. Another gap was thus formed between (Ashkenazic) Jewish law and Islamic law.

Another example of this pattern is the question of the lineage of a child of a mixed marriage, which in the Bible, according to critical consensus, was based on patrilineal descent, whether in marriages between Jews or between a Jew and a non-Jew. This principle was later superseded by that of matrilineal descent, based on a midrashic exposition of Scripture, in response to changing realities. The Mishnah reports the final stage in a process of halakhic change that had presumably begun beforehand, which ultimately became the halakhic norm: "Whatever [woman] cannot be betrothed to that particular person or with others, the issue follows her status; this is the case with the issue of a bondmaid or a gentile woman" (Kid. 3:12). Islamic law, however, maintained the principle of patrilineal descent (probably because Islamic law permits a Muslim man to marry a non-Muslim woman).

At times, the change in Jewish law can be attributed to changed values in the rabbinic world, such as the midrashic redefinition of the term na'arah (unmarried girl), previously understood as designating status (as in the Bible): the Midrash redefines the term as denoting a young girl between certain age limits, so that a woman beyond those limits was considered independent. By contrast, in some schools of Islamic law, the cognate term continued to designate status, the girl remaining under her father's authority irrespective of her age. Similarly, the rabbinic interpretation of the scriptural verse "an eye for an eye" as referring not to physical retribution but to monetary compensation, has no parallel in Islamic law, which has retained the literal meaning of the phrase.

Both Islamic and Jewish law recognized the legitimacy of disagreement and legal pluralism, epitomized in the latter by the talmudic saying, "Both [conflicting opinions] represent the words of the living God." In Islamic law, however, this principle received prominent normative significance, in the sense that it granted equal status to different legal schools. This situation made adjustment to changing realities possible by transferring the focus of legal development from the text to the personality at the head of a particular school. A diversity of opinions was thus generated, making for a more flexible machinery of legal decision and somewhat compensating for the lack of dynamic sources of the law. Jewish law, however, from the start, adopted a rigid system of decision rules, unparalleled in Islamic law, meant to guide the halakhic decisor in dealing with differences of opinion. This somewhat limited the Halakhist's freedom to deviate from the halakhic text.

Legal Literature in Jewish and Islamic Law

The legal bases of the two systems, stemming as they did from diverse theological differences, affected their respective genres of literary creativity, as well as the nature and function of those genres. A basic similarity between the Bible and the Qur'ān is that both laid the normative groundwork for their respective legal systems, transforming in part earlier practices. In both, the legal material occupies only part of the text, which also includes a good measure of narrative. The Muslims evolved a special literary genre for the legal material of the Qur'ān, known as Aḥkām al-Qur'ān, "Laws of the Qur'ān," reminiscent of the contemporary Jewish genre of Sefer ha-Mitzvot.

Yet, the differences between the two systems outweigh the similarities. Primary is the difference in their mode of revelation. The theophany at Sinai was the sole source of the Torah, whereas the Qur'ān, according to Muslim tradition, was "brought down" from heaven, chapter by chapter, over 20 years. This gave rise to contradictions between different sections, leading to a criterion of "early" and "late" – later verses that repealed earlier ones – and as a result generated a genre specific to Islamic law to resolve such contradictions (Kitābal-nāsikh wa'l-mansūkh). In Jewish law, however, the ruling principle was that no differentiation could be made between "early" and "late" material, and there was no need of such a genre. Instead, what emerged was recognition of an Oral Law accompanying the Written Law.

A special feature of Jewish legal tradition was the development, especially in the late Second Temple period and for some time afterwards, of literary genres designed to "prove" the Oral Law as being embodied in the Written. These "proofs" formed the basis for the compilations known collectively as "Halakhic Midrash," as edited in the rival schools of R. Akiva and R. Ishmael. Both schools evolved a system of hermeneutical rules for the presentation of the Oral Law as embodied in Scripture. Tradition makes Hillel the Elder the expounder of seven such rules, expanded later by R. Ishmael to 13. Among the more familiar of these rules are kal va-ḥomer (argument a forteriori), gezerah shavah (comparison of similar expressions), binyan av (inference from a particular case), davar ha-lamed me-inyano (argument from context). Two general rules of scriptural interpretation, outside the realm of hermeneutics, are the principles: "The Torah speaks in human language" and "The Torah speaks of the present [situation]" (both enunciated by the school of R. Ishmael). These rules, instrumental in the confirmation of Oral Law, are unparalleled in the Muslim legal literature.

The two systems differ in other branches of legal creativity, some deriving from theological reasons, others from the particular practical needs of each system. Exceptions are certain literary genres in which Jewish literary creation emulated its Muslim counterpart, in view of similar needs – such as the appearance of halakhic monographs on a variety of topics. Sometimes, despite a superficial similarity of literary function, the structure of the work is quite different. Thus, while both systems in time committed their oral traditions to writing – though both had originally forbidden such a procedure – there are still fundamental, theologically based, differences in the methods of transmission, the level of authenticity of a tradition, and its sources. In Jewish law, the main sources of the Oral Law are the Mishnah, the Tosefta, and the Halakhic Midrashim. The transmission tradition that establishes the validity of the Oral Law was enunciated at the beginning of Tractate Avot of the Mishnah: "Moses received the Torah at Sinai and transmitted it to Joshua, and Joshua transmitted it to the Elders, and the Elders to the Prophets, and the Prophets transmitted it to the men of the Great Synagogue…" Thus, the Oral Law (tradition) is firmly rooted in a divine source and is the basis of the authority of the editor of the Mishnah, R. Judah ha-Nasi. Muslim oral law, the Sunna, however, consisted of diverse collections of traditions, all endowed with canonical status; these were also based on chains of transmitters, but there the similarity ends: The isnād (chain of transmitters) is personal rather than institutional, extending from the last authority in the chain to the first, who is closest in time to Muhammad or his companions; each law needs its own isnād as proof of its truth and authenticity. While rabbinic literature sometimes presents a similar concept of a chain of transmission, it is generally shorter and not necessarily based on names (such as the Mishnah, Eduyot 8:7; see Cook, "Opponents of the Writing of Tradition," pp. 510–11), though at times a chain of tradition combines both personalities and institutions (as in the Mishnah, Pe'ah 2:6). Some scholars believe that such chains were the model for the Muslim concept, which in turn had its influence on Jewish chains of tradition in later literature, in a kind of feedback effect; in the Mishnah and the Talmud, however, they were not a precondition for the validity of a law or a criterion of its authenticity. Because of this feature of Islamic law, there was a phenomenon of artificial chains as well as attempts to attribute late laws to the prophet himself. A similar phenomenon of attribution to prestigious authorities may also be found in geonic literature.

Around the same time as the consolidation and redaction of Sunna collections in Islamic law – a process that took more than 200 years, from the 9th to the mid-11th century – the genre of halakhic responsa evolved in Jewish law, to meet the needs of Jewish communities throughout the East. This genre made an inestimable contribution to the development of Jewish law and is unparalleled in contemporary Islamic law.

The different contemporary developments – emergence of the Sunna in Islam and of responsa literature in Judaism – reflect the different legal and historical needs of the two systems. Islam focused on the consolidation of a legal tradition and its attribution to Muḥammad, through the existence of independent legal centers in the Muslim world, which obviated the need to appeal to a single center. Jewish law, in contrast, was based on the already consolidated Oral Law; thus the leading legal center of authority in Iraq strove to decide questions of law generally, throughout the Jewish Diaspora, and with the institution of the responsum maintained its central position in the world of Jewish law. The responsa literature also served as a kind of corpus of legal precedents, again a phenomenon with no parallel in contemporary Muslim legal literature.

A further literary genre characteristic of Islamic law, but with no counterpart in Jewish law was that concerned with the "roots" of Islamic law, Uṣūl al-fiqh, that is, defining the legal sources of Islamic law, its theoretical bases, and rules for the derivation of rules from the "roots." This genre was necessary because of the confrontation between the supporters of tradition (ahl al-ḥadīth) and the supporters of legal theory (ahlal-ra'y). The quite intense tension between these two groups required tools to define legal theory and the limits and rules of legal methodology. These tensions hardly existed in the rabbinical world of halakhah, where a separate branch of legal theory was not necessary. Such topics were nevertheless taken up on the periphery of legal writing, as in the works of R. Saadia Gaon and R. Samuel b. Ḥofni on scriptural exegesis, or in specialized works such as those written by Karaites in the same period; these works, however, did not constitute an independent halakhic genre.

Yet another specifically Islamic creation was the literature of legal devices or evasions (ḥiyal). Certain topics elaborated in Islamic legal theory resulted in significant discrepancies between what was taught in the law schools and the reality of practice, such as the prohibition of usury. The ḥiyal literature tried to bridge this gap between theory and practice by way of various legal devices or fictions (such as the "double sale" of property in order to circumvent the prohibition of usury). While Jewish law also makes use of legal fictions (in the geonic period – perhaps owing to Muslim literature), this never reached proportions that dictated the composition of specialized works on the subject, especially since the legal substrate available to Jewish law, as described above, obviated the need for such works.

The literature of "disagreements" (ikhtilāf), which concerned itself with disagreements between Muslim jurists over a broad spectrum of subjects, is not characteristic specifically of Islamic law. Indeed, a similar genre existed in pre-Islamic Jewish law – the literature of ḥillukim. Again, however, the difference was significant: the Muslim genre had to cope with the existence of multiple legal opinions so as to ensure the equal status of the different legal schools; no such need existed in contemporary Jewish law. The Muslim formularies (shurūṭ) also aimed to harmonize the rulings of the different legal schools.

The one field in which the geonim clearly took Muslim literature as a model was the writing of halakhic monographs, frequently on the very same topics. We thus have works on the duties of judges and formularies, among dozens of works on a variety of subjects. In this area the fuqahā' (religious lawyers of Islam) and the geonim had a similar goal: to help their contemporaries conduct themselves in accordance with the law and to inculcate a common vocabulary (lingua franca) of terms and concepts. The geonim made use of such works, written in Arabic, and their legal terminology, which they used as a contemporary frame of legal composition. The flourishing legal literature of the geonic period was made possible thanks to the Muslim authorities, who granted their non-Muslim "protected" subjects, the dhimmīs, including the Jews, legal autonomy, spurring the growth of a ramified legal literature in a contemporary legal form.

There was nevertheless a significant difference in the writing of legal monographs in both systems: The Muslims would write comprehensive works on the totality of legal topics, whereas the geonim as a rule devoted a separate work to each topic. Later, however, it was these specialized works that provided the basis for the great comprehensive work of codification, in particular, for Maimonides' Mishneh Torah. Such codificatory activity was made possible by the existence of the rules of decision of Jewish law, which provided the backbone for these literary efforts. In Islamic law, however, with its pluralistic nature and the absence of an agreed system of rules of decision, the codificatory nature of the Muslim legal monographs was less obvious. The phenomenon of codification, which was unique to Jewish legal creativity under Islam (including R. Jacob b. Asher and his Arba'ah Turim, R. Joseph Caro and his Shulḥan 'Arukh), created a gap between the Spanish and Middle-Eastern works of halakhah and contemporary writing in Franco-Germany, where there was no such codificatory activity. This, then, is yet another example of the way Islamic law influenced the development of Jewish law in Eastern countries, sometimes leading to a veritable division between the Spanish and Middle-Eastern variety of Jewish law and that current in Franco-Germany (Ashkenaz), a division sometimes evident even in the actual content of specific laws.


M. Cook, "The Opponents of the Writing of Tradition in Early Islam," in: idem, Studies in the Origins of Early Islamic Culture and Tradition (2004); R. Drory, Models and Contacts: Arabic Literature and its Impact on Medieval Jewish Culture (2000); A. Geiger, Was hat Mohammed aus dem Judenthum aufgenommen, rev. ed. (1902); S.D. Goitein, "The Interplay of Jewish Law and Islamic Law," in: B.S. Jackon (ed.), International Conference on Jewish Law in Legal History and the Modern World (1980), 61–77 [= R. Link-Salinger (Hyman) (ed.), Jewish Law in Our Time (1982), 55–76]; idem, "The Stern Religion: Some Comments on the Portrayal of Judaism in Early Muslim Literature," in: M. Schwabe et al. (eds.), Dinaburg Jubilee Volume (1949), 151–64, 423 (Heb.); M.J. and M. Kister, "On the Jews of Arabia; Some Notes," in: Tarbiz, 48 (1979), 231–47 (Heb.); M.J. Kister, "Ḥaddithu 'an Bani Isra'il wa-la ḥaraja: A Study of an Early Tradition," in: Studies in Jahiliyya and Early Islam (1980), 215–39; J. Kraemer, "The Influence of Islamic Law on Maimonides: The Case of the Five Qualifications," in: Te'udah, 10 (1996), 225–44 (Heb.); H. Lazarus-Yafeh, "Some Halakhic Differences between Judaism and Islam," Tarbiz, 51 (1982), 207–22 (Heb.); G. Libson, Jewish and Islamic Law: A Comparative Study of Custom During the Geonic Period (2003). idem, "Islamic Influence on Medieval Jewish Law?" Sefer Ha'arevuth (Book of Surety) of Rav Shmuel ben Ḥofni Gaon and Its Relationship to Islamic Law," in: Studia Islamica, 73 (1991), 5–23; idem, "More on the Relationship of Rav Shmuel ben Ḥofni Gaon's Sefer Hamatzranot to Islamic Law," in: D. Boyarin et al. (eds.), 'Atara L'Ḥaim in Honor of Professor H.Z. Dimitrovsky (2000), 371–409; J.R. Wegner, "Islamic and Talmudic Jurisprudence: The Four Roots of Islamic Law and Their Talmudic Counterparts," in: The American Journal of Legal History (1982), 25–69; M.R. Zucker, Saadya's Commentary on Genesis (1984), 11–69; A. Zysow, Ẓadaka, in: ei2 (1995), 8, 708–15.

[Gideon Libson (2nd ed.)]

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