if she was married to any of his forefathers; the wife of his son, no matter how far down the line; and his wife’s mother. Once he has consummated the marriage with his wife, her daughter and the daughter of her son likewise become permanently forbidden to him.

Outside a valid marriage contract, no woman becomes prohibited through affinity unless actual intercourse—vaginal or anal—has taken place, the male being at least ten years old and the female nine, with both still alive. Intercourse with a male produces the same prohibitions as intercourse with a female. Neither the mother nor the daughter of his father’s wife, or of his son’s wife, is barred to him.

Section

It is unlawful to combine in marriage two sisters, or a woman together with her paternal or maternal aunt. Whoever marries, for example, two sisters in a single act or in two simultaneous contracts has contracted an invalid marriage. If he did so unknowingly, a judge annuls both contracts and, by drawing lots, grants one of the women half of her dower. If the contracts were concluded sequentially, only the first is valid.

If a man owns two slave-women who are sisters, or women in a comparable relationship, that ownership stands. He may have intercourse with whichever he chooses, while the other becomes forbidden to him until he renders the one he has slept with unlawful to himself by removing her from his ownership or by marrying her off to another man after her istibraʾ waiting period.

Should a man have intercourse with a woman under a mistaken belief of permissibility (shubha) or through fornication, it is forbidden—for the duration of her waiting period—for him to marry her sister, or to have intercourse with that sister if she is already his wife or his slave. During this period he may not exceed three other women besides her, whether through marriage contracts or intercourse.