Cohabitation between a man, married or unmarried, and an unmarried woman. While the common law speaks of intercourse between a married man and an unmarried woman as adultery, followed herein by many American statutes which grant a divorce for the "adultery of the husband," the Authorized Version of the Old Testament uses the word "fornication" four times, always in a figurative sense. In the New Testament it stands for the Greek πόρνεια; and as a husband is bidden not to divorce his wife except for this offense, the word is there evidently an equivalent for "adultery."
As to the gravity of this offense there is difference of opinion. Deuteronomy xxiii. 18 (A. V. 17) says: "There shall be no harlot ["ḳedeshah"] of the daughters of Israel." A ḳedeshah is, according to rabbinic commentators, a woman who sells herself to every comer, and stands far apart from the virgin who is "enticed" or seduced (Ex. xxii. 16). The former is liable to flagellation, as breaking a negative law; the latter is treated as the injured party, to whom the seducer must make amends; and the seducer is not liable to stripes, for his penalty is named: he must marry the girl if her father will consent.
The standard edition of the Sifre on Deuteronomy xxiii. 18 throws no light on the text; but an old manuscript of this work, referred to in Maggid Mishneh in a gloss on Maimonides' "Yad," Ishut, i. 4, says that the text intends to forbid any sexual intercourse between a man and a woman not his wife. Maimonides himself (ib.) holds that as a matter of Mosaic law both parties are liable to stripes. Abraham ben David dissents, taking the ground that a woman who gives herself over to only one man is not a ḳedeshah, but a concubine ("pillegesh"), according to the Bible (see II Sam. v. 13)—a wife without the ceremony of betrothal and without jointure (see Ketubah)—and that neither she nor her lover is guilty of any Scriptural offense. The Shulḥan 'Aruk (Eben ha-'Ezer, 26, 1) takes a middle ground, admitting that the case in question does not fall under the heading of "ḳedeshah," but asserting that, in the interest of modesty, both are forbidden by custom and rabbinical law, and should be repressed, if need be, by the infliction of stripes ("makkat mardut"). It is even forbidden to be alone with a woman in a room (ib. 22, 2).
Intercourse of a son or daughter of Israel with a Gentile, or with a foreign slave, with whom there can be no valid betrothal, is discussed by the authorities in a twofold aspect: (1) If the relation is permanent, making them in fact husband and wife, it comes under the head of fornication only in so far as Jewish law does not recognize such a relation as a true marriage; the main objection, however, arises in the religious interest of the children (see Ex. xxxiv. 16). (2) Casual cohabitation, which stands on different ground. The Mishnah (Sanh. ix. 6) names him "who cohabits with a Syrian woman" (with a Gentile, an idol-worshiper) among those whom the zealots may strike down; and while this rule, based on the example of Zimri and Phinehas (Num. xxv. 7), was rendered harmless by impossible conditions, the rabbinical courts under an institution of the Hasmoneans, attested in the Babylonian Talmud by two of the later sages (Sanh. 82a), would consider such an offender as deserving punishment upon four distinct grounds, one of them being that of implied idol-worship. This is based on the words of the prophet Malachi (ii. 11, Hebr.): "For Judah has profaned the sanctuary of the Lord which he loved, and has cohabited with ["ba'al"] the daughter of a strange god."