The Covenant That Draws the Map

About This Talk

Chapter 2 of Hilchot Issurei Biah maps the relatives forbidden by blood and by marriage. Four women are forbidden to a man forever, whether betrothed or married, during their husbands' lives or after, even if divorced: his father's wife, his son's wife, his brother's wife and his father's brother's wife, except the widow of a brother who died childless, who is subject to yibbum. Relations with one of them during her husband's lifetime incur two sin offerings, for kinship and for adultery, and relations with one's mother who is also his father's wife incur two as well, during the father's life or after. The wives of both paternal and maternal brothers are forbidden, regardless of whether either was born in or out of marriage, while the wife of the father's maternal brother is only a rabbinic shniyah. A sister from either parent is forbidden whether born in or out of marriage. The daughter of one's father's wife who is also one's father's child carries an additional prohibition, so relations with a sister born to the father's wife in marriage incur two offerings; but the daughter of one's father's wife from another man is permitted, and a sister born of the father's relationship outside marriage incurs only the prohibition of a sister. The sisters of one's mother and father are forbidden whether born in or out of marriage. A daughter born to a man outside of marriage is forbidden by Torah law, which is implied by the prohibition of a daughter's daughter; with a daughter of his wife he incurs two offerings. When a man betroths a woman, six of her relatives become forbidden to him forever, whether he marries or divorces her, during her life and after her death: her mother, mother's mother, father's mother, daughter, daughter's daughter and son's daughter. During his wife's lifetime relations with them are punishable by burning; after her death they carry kareit but no court execution. His wife's sister is forbidden only during his wife's lifetime, whether paternal or maternal, born in or out of marriage. If he transgresses with one of these seven, his wife is not forbidden to him, except in the case of the sister of a woman he betrothed, as explained in Hilchot Gerushin. A relationship outside of marriage does not make the woman's relatives forbidden by Torah law, but the Sages forbade marrying her relatives during her lifetime lest familiarity lead to transgression; one merely suspected should not marry her relative during her lifetime, though if he did he need not divorce. One suspected or rumored to be involved with an ervah should not live on her lane or appear in her neighborhood, as in the incident of the man disciplined for passing his mother-in-law's door. Relations outside marriage with a woman and her daughter or sister count as two unrelated women, and a woman violated or seduced by one's father, son, brother or father's brother is permitted to him, since the verses speak of marriage. A man whose father or son married a woman may marry her mother or daughter; he may marry the widow of his brother's son, and a woman together with her sister's or brother's daughter. It is a mitzvah from the Sages to marry one's sister's daughter, and according to the Rambam one's brother's daughter, based on Isaiah 58:7.