EMDEN, JACOB (pen name Yaveẓ ; derived from Y a'akov B en Ẓ evi; 1697–1776), rabbi, halakhic authority, kabbalist, and anti-Shabbatean polemicist. Emden was regarded as one of the outstanding scholars of his generation. Emden's teacher was his father Ẓevi Hirsch *Ashkenazi (Ḥakham Ẓevi). He inherited his father's interest in secular studies, his dissociation from the Ashkenazi method of study (pilpul) and customs, his stormy, independent, and uncompromising character, and his devotion to the campaign against the Shabbateans and their sympathizers. In addition, he possessed a fine literary talent, a critical tendency, and a knowledge unusual for his age of general non-halakhic Jewish literature. He was also familiar with sciences and languages (German, Dutch, Latin). Despite his distinguished descent and his remarkable talmudic attainments, Emden occupied no official position, with the exception of a few years as rabbi of Emden (1728–33). This made it possible for him to be exceptionally critical toward the society and the tradition of his time. He was more on guard about anything that he considered ḥillul ha-Shem (bringing the name of the Jew into disrepute) than for the good name of the rabbinate and of the community. He made extensive use of the private printing press he founded in *Altona to disseminate his views. As a result, because of his views on a number of issues, both personal and communal, he became a figure of contention. His important halakhic works are Leḥem Shamayim, on the Mishnah (pt. 1, 1728; pt. 2, 1768); a letter of criticism against R. Ezekiel Katzenellenbogen, rabbi of Altona (1736); responsa, She'elat Yaveẓ (2 pts., 1738–59); Mor u-Keẓi'ah, on the Shulḥan Arukh, oḤ (2 pts., 1761–68). In addition, he published an important edition of the prayer book (whose parts had different names) with a valuable commentary (1745–48). This prayer book was reprinted several times. His main historical importance lies in his campaigns against the Shabbateans to which he dedicated many years. He relentlessly examined and investigated every suspicious phenomenon pertaining to the sect. He called upon the contemporary rabbis to publish excommunications and mercilessly attacked anyone suspected of supporting or showing sympathy to the Shabbateans. The Shabbateans were accustomed to introduce hints of their secret doctrine into their literary works, particularly in the field of Kabbalah. Consequently, Emden became an expert in uncovering such allusions and hidden meanings, and developed an extraordinarily sharp critical faculty by which he could recognize any suggestion of the Shabbatean heresy. Many books in which no one saw anything to which objection could be taken, were condemned by him as heretical. Though at times he was at fault and suspected the innocent without cause, his judgment in general was sound (F. Lachover and I. Tishby (eds.) Mishnat ha-Zohar, 1 (19572), 52–56).
His most famous controversy was with Jonathan *Eybeschuetz, rabbi of the "Three Communities" (Altona, Hamburg, Wandsbek) from 1750 until he died in 1764. It commenced in 1751 soon after Eybeschuetz came to Altona and did not cease even with the latter's death. It divided German Jewry, particularly rabbinic circles, into two camps, and undermined the prestige of rabbinical institutions.
The conflict at first centered around several amulets which Eybeschuetz circulated in Metz and Hamburg. Emden published their content in his work Sefat Emet u-Leshon Zehorit (1751) and interpreted them rather convincingly as Shabbatean amulets. As a result of this publication, Emden was compelled to escape to Amsterdam for some time and there he published in Torat ha-Kena'ot (1752) an anthology of documents on Shabbateanism. Eybeschuetz too was a great scholar; he had devoted disciples but also many enemies. He was suspected of adhering secretly to the Shabbatean groups or at least of affinity to them. His son was a declared Shabbatean. Eybeschuetz denied the accusation, which in any case could not be proved with certainty. The majority of the greatest rabbis in Poland, Moravia, and Bohemia, as well as the leaders of the Three Communities supported him, either because the accusation was utterly incredible, or because condemnation of a rabbi who enjoyed such an enormous prestige as Eybeschuetz would cause inestimable damage to the communal organizations as a whole. Emden disregarded these considerations vehemently. He fought his opponent and his numerous supporters by means of books and pamphlets which came out in unabated succession.
Emden's major works in this dispute, apart from several small pamphlets and leaflets, are Edut be-Ya'akov (1756); Shevirat Luḥot ha-Even (1756–59), a detailed critique of the defense of Eybeschuetz; Luḥot Edut, Sefer Hitabbekut (1762–67), which also includes important protocols on the Shabbatean propaganda activities in the yeshivah of Eybeschuetz in Hamburg and in the great yeshivah in Pressburg. In addition, Emden dedicated his Sefer Shimmush as "a special weapon for every Jew to use in order to know what to answer to the Shabbatean groups" (1758–62) and to fight Frankism, which arose in his time. The two opposing camps in Altona requested the intervention of the authorities and it was only through this intervention that the conflict subsided.
From this campaign, Emden went on to criticize the Zohar, the bastion of the Shabbateans (see *Kabbalah). The Zohar was regarded by many as second only to the Bible in sanctity. Emden had questioned its antiquity, and consequently its sanctity in Mitpaḥat Sefarim (1768), which provoked opposition. His piety and profound attachment to tradition would not permit him to condemn the work as a whole. Nevertheless, he did not hesitate to state his conclusion that later and forged additions had been interpolated into an ancient and sacred book. His critical attitude toward accepted ideas and beliefs is revealed also in his criticism of the Guide of the Perplexed, the major work of Jewish philosophy, which he found to contain heretical tendencies; he did not believe that *Maimonides was its author. His activity in many directions as well as his general approach which he based on the use of grammar, philology, and history and the like, his brilliant and scholarly style, his tolerant attitude to Christians and his deprecation of Polish Jews, created a certain affinity between him and the first proponents of Haskalah, who had already emerged in his day, and most of whom were opposed to the Kabbalah and its influence. Although in fact Emden rejected philosophy and scientific criticism in the sphere of Judaism, permitting only the study of the natural sciences, he was friendly with Israel of Zamosc and his disciple, Moses *Mendelssohn. He held discussions with them on halakhic topics, customs, and principles of religion. From the correspondence between Emden and Mendelssohn, the difference between the maskil of the old school such as Emden and the new type such as Mendelssohn emerges clearly.
The independence, originality, and stormy temperament of Emden are noticeable in his halakhic works. In certain subjects he takes up an extreme view against the majority opinion, and in others he is outstandingly lenient (e.g., with regard to concubinage and eating legumes during Passover). In a dispute with Israel of Zamosc on the authority of the Shulhan Arukh, it was precisely Emden who upheld the principle of the freedom of the posek (halakhic authority), from dependence on this code. Emden's autobiography, Megillat Sefer (first published from an Oxford Ms. in 1896), is unique in the rabbinic world. In addition to its historical importance it is of no small belletristic value.
Emden's ability as a grammarian is evident in his commentary on the prayers (Siddur Beit Ya'akov), where he combines grammatical comments and kabbalistic commentary. He explains, for example, that barukh is not a passive past participle but a noun like raḥum, the kamaẓ compensating for the lack of a dagesh in the letter resh. In consequence he arrives at the explanation that God is the source of blessings. He also discusses mishnaic Hebrew (e.g., the word "Nishtannah" as a conflation of nifal and hitpa'el). In his commentary on the Mishnah Leḥem Shamayim, he discusses variant readings, determining the correct one by linguistic considerations. Em la-Binah, his commentary on Scripture, abounds in inferences drawn from differences between synonyms, and Gal Ed contains discussions on correct vocalization.
M.J. Cohen, Jacob Emden, a Man of Controversy (1937); G. Scholem, in: ks, 16 (1939/40), 320–38; Y. Raphael, in Aresheth, 3 (1961), 231–76; B.-Z. Katz, Rabbanut, Ḥasidut, Haskalah, 1 (1957); A. Shochat, Im Ḥillufei Tekufot (1960), index; J. Katz, Exclusiveness and Tolerance (1961), index; M.A. Wagenaar, Toledot Yaveẓ (1868); D. Kogan, Toledot ha-Mekubalim ha-Shabbeta'im ve-ha-Ḥasidim, 2 (1913), 27–64; A.R. Malakhi, in: Hadoar, 18 (1938–39), 155–6; M. Grunwald, Hamburgs deutsche Juden (1904), 89–124.
[Moshe Shraga Samet]