BAT KOL (Heb. בַּת קוֹל; lit. "daughter of a voice," i.e., an echo of a heavenly voice, or a divine voice "once removed"), a heavenly or divine voice which revealed God's will, choice, or judgment to man. According to rabbinic tradition, the bat kol was already heard during the biblical period. It proclaimed Tamar's innocence; declared that the prophet Samuel had not materially benefited from his public position; and validated Solomon's judgment in awarding the child to the true mother (Mak. 23b). Before the death of Moses, a heavenly voice proclaimed that God Himself would attend to his burial (Deut. R. 11:10), and after his death a bat kol heard over an area 12 miles square announced his demise (Sot. 13b). A bat kol informed David that Rehoboam and Jeroboam would divide his kingdom (Shab. 56b); and when Solomon sought to emulate Moses a heavenly voice rebuked him (rh 21b). According to the Talmud a bat kol was often heard at the death of martyrs. After the death of the mother and her seven sons (see *Hannah and Her Seven Sons), a voice proclaimed: "A joyful mother of children" (Ps. 113:9; Git. 57b). When Ḥanina b. Teradyon was cruelly executed, a bat kol called out: "R. Ḥanina b. Teradyon and the Roman who hastened his death have been assigned to the world to come" (Av. Zar. 18a). After R. Akiva's execution, a "heavenly voice" resounded: "Happy art thou, R. Akiva, that thou art destined for the life of the world to come" (Ber.61b). When a Roman officer sacrificed his life so that R. Gamaliel ii would be spared, a bat kol declared: "This high officer is destined to enter into the world to come" (Ta'an. 29a).
With the cessation of prophecy, the bat kol remained the sole means of communication between God and man (Yoma 9b). In most instances, where reference is made to a bat kol, it refers to an external voice which is heard by the recipient of the message. However, at times the bat kol was only perceived in dreams (cf. Ḥag. 14b). The "heavenly voices" mentioned in stories concerning R. Bana'ah (bb 58a) and Rabbah b. Bar Ḥana (bb 73b–74a) also were heard in dreams (see Chajes in bibl.).
The authority granted to a bat kol in determining halakhah is discussed in two different talmudic passages. In one instance, after three years of controversy between Bet Sham-mai and Bet Hillel, the sages accepted a bat kol's pronouncement that "the words of both are the words of the living God, but the halakhah is in agreement with the rulings of Bet Hillel" (Er. 13b). However, R. Joshua refused to abide by a bat kol which ruled in favor of R. Eliezer in his dispute with the sages regarding the ritual purity of the oven of "Akhnai" (bm 59b). R. Joshua explained that the Torah "is not in heaven" (Deut. 30:12), and therefore no attention is given to a "heavenly voice," and it is rather the majority of the sages who determined the halakhah. Later commentaries accepted R. Joshua's viewpoint, and explained that the bat kol was only effective in determining the ruling in the Bet Shammai and Bet Hillel controversies, since the sages were themselves in doubt whether to rule in accordance with the larger school of Bet Hillel or the more profound thinkers of Bet Shammai (Tos. to Er. 6b s.v. כאן).
A. Guttmann, in: huca, 20 (1947), 363–406; E.E. Urbach, in: Tarbiz, 18 (1946/47), 23–27; idem, Ḥazal (1969), 516; S. Lieberman, Hellenism in Jewish Palestine (1950), 194–9; Z.H. Chajes, Student's Guide to the Talmud (19602), 212–3.