According to the Bible, adultery is a serious sin. The Ten Commandments forbid it, and Leviticus and Deuteronomy say that couples who commit adultery must die. The prophets condemn adulterous men and women, the book of Proverbs warns against adultery, and the New Testament writers view adultery as sinful.
But on closer examination, the definition of adultery in much of the Hebrew Bible is one-sided. Men did not have to be faithful to one woman. They could have more than one wife (Deut 21:15), and even for married men, sleeping with unmarried or unbetrothed women did not count as adultery (Exod 22:16-17, Deut 22:28-29). Only men who slept with another man’s wife or fiancée could be punished for adultery, along with the woman concerned (Deut 22:22-26). But a woman had to be faithful to her husband alone and was expected to be a virgin until she married (Deut 22:13-21). This points to a society that valued men above women, in which men had social and political power and women’s role was to serve men’s interests.
One very important way in which men needed women was to produce sons who would carry on the family name, inherit the family’s land, and provide support in old age. But women might be barren or die in childbirth, and children, too, often died young. So a man might well need more than one wife at a time if he was to father sons who would survive to adulthood.
But he also needed to know that his sons were really his own: if his wife slept with another man, it threatened her husband’s line of descent and cast a slur on his manhood. It also challenged the convention that women were under men’s authority; so an adulterous woman was a very dangerous person. Just how dangerous is clear from the fact that, unlike the adulterous man, the adulterous woman is an independent motif of sinfulness, particularly in the Hebrew Bible.
The prophets Hosea, Jeremiah, and Ezekiel all use the metaphor of an adulterous woman to condemn the people of Israel who have been unfaithful to Yahweh, their “husband,” by worshiping other gods. The metaphor reflects the male-female power dynamics that would have existed in a marriage: the all-powerful deity who is entitled to demand absolute loyalty is represented by the husband, the male, whereas the people, who are supposed to be obedient and dependent, are represented by the wife, the female. But there is no equivalent metaphor of an adulterous man.
Another significant example of the adulterous-woman motif appears in Num 5:11-31, where the law allows a man who suspects his wife of adultery to make her undergo an ordeal in front of the priest to test whether or not she has been unfaithful. No such ordeal exists for men. Similarly, the book of Proverbs warns young men against women who take advantage of their husbands’ absence to entice strangers into sexual relations (Prov 7:10-20). But no biblical book warns women against men who might try to entice them away from their husbands.
In the New Testament several writers warn men against adultery (e.g. 1Cor 6:9, Heb 13:4). But the only story that focuses on adultery uses the adulterous woman motif. In John 7:53-8:11, the Pharisees bring to Jesus a woman caught in adultery and ask Jesus if he thinks that she should die for her sin, as the Jewish law demands. But they do not mention her male partner, who is completely absent from the account. Clearly, in the male-focused world of the Bible, all adultery was a crime, but adulterous women were seen as much more dangerous and subversive than adulterous men.