From the earliest biblical days adultery carried with it a sense of defilement, so that a woman who had know contact with another man, even if by force, was considered no longer fit to be visited by her husband (Genesis 49:4; 2 Samuel 20:3, . 16:21-22; Book of Jubilees 33:6-9; Epstein, , p.51). The Deuteronomic code teaches that a woman who is divorced by her husband and thereafter marries another man likewise cannot return to her former husband (Dt 24:1-4). As the Lord said through the prophet Jeremiah: “If a man put away his wife and she goes from him and becomes another man’s wife, shall he return to her again, shall not the land (his wife’s body) be greatly polluted?” (Jr 3:1; see <Targum to Dt 24:1-4)>. In rabbinic law a woman who has committed adultery is “defiled” and cannot remain the wife of her husband, but must be divorced <(Sifre on Dt>, edit. M. Friedman (1864) 270 p. 122b; , edit. M. Friedman (1915) 7 p. 4a and 19 p. 66). Furthermore any intimate male contact by the wife with Jew or gentile, potent or impotent, natural or unnatural makes divorce compulsory <(Sotha> 26b; 55a, b, 87b; 9a, Babylonian Talmud<; Kethuboth> 25a; 27a, <Yad, Sotah> 22, Jerusalem Talmud).
In Jewish Law a man betrothed to a woman was considered legally married to her. The word for betrothed in Hebrew is , a word that is derived from the Hebrew word which means “holy” “consecrated,” “set apart.” Because by betrothal (as in Mt 1:18; Lk 1:27) , or marriage, a woman became the peculiar property of her husband, forbidden to others. The (Marriages and Engagements) states; “The husband prohibits his wife to the whole world like an object which is dedicated to the Sanctuary” <(Kiddushin> 2b, Babylonian Talmud). We know from the Gospel of Matthew 1:14 that Joseph the husband of Mary was a righteous man, a devout law-abiding Jew. Having noticed that Mary was pregnant and that he, her betrothed, had nothing to do with the pregnancy, Joseph had either to publicly condemn her and have her put to death for adultery (Dt 22:22-29) or put her away privately. His decision was made when an angel appeared to him in a dream, saying: “Joseph, son of David, do not fear to take Mary as your wife; for that which is conceived in her is of the Holy Spirit; she will bear a son, and you shall call His name Jesus, for He will save His people from their sins” (Mt. 1:20-21). The angel does not use the phrase for marital union: “go in unto” (as in Gn 30:3, 4, 16) or “come together” (Mt 1:18) but merely a word meaning leading her into the house as a wife <(paralambano gunaika)> but not cohabiting with her. For when the angel revealed to him that Mary was truly the spouse of the Holy Spirit, Joseph could take Mary, his betrothed, into his house as a wife, but he could never have intercourse with her because according to the Law she was forbidden to him for all time.
We also have to take into consideration that when Mary was told by the archangel Gabriel “Behold, you shall conceive in your womb, and bring forth a Son, and you shall call His name Jesus” (Lk 1:31), he also added that this was to come about because “The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the Holy one to be born shall be called the Son of God” (Lk 1:35). By stating it in those terms the archangel declared to Mary that God would enter into a marital relationship with her, causing her to conceive His Son in her womb, For “to lay one’s power <(reshuth)> over a woman” <(Targum to Dt> 21:4) was a euphemism for “to have a marital relationship with her.” Likewise “to overshadow” (Lk 1:35) by spreading the “wing” or “cloak” over a woman was another euphemism for marital relations. Thus, the rabbis commented <(Midrash Genesis Rabbah> 39.7; 3.9) that Ruth was chaste in her wording when she asked Boaz to have marital relations with her by saying to him “I am Ruth you handmaid, spread therefore your cloak ( literally, “wing”: <kanaph)> over your handmaid for you are my next-of-kin” (Ruth 3:9). , another Aramaic-Hebrew word for cloak, is derived from = shadow. Thus, “to spread one’s cloak <(tallith)> over a woman” means to cohabit with her <(Kiddushin> 18b, see also <Mekhilta on Exodus 21:8)>. Did not the Lord say to His bride Israel: “I am married to you” (Jr 3:14) and “your Maker is your husband”? (Is 54-5:5; Jr 31:32)? And what is more intimate than what the Lord said to His bride: “You developed, you grew, you came to full womanhood; your breasts became firm and your hair grew… you were naked… and I saw that you were now old enough for love so I spread my cloak over you… I gave you My oath, I entered into a covenant with you and you became Mine, says the Lord God” (Ezk 16:7, 8).