Leviticus 18:15-18

¹⁵Don't have sex with your daughter-in-law. She is your son's wife. Don't have sex with her.

¹⁶Don't have sex with your brother's wife and bring shame on your brother.

¹⁷Don't have sex with both a woman and her daughter. Don't have sex with her son's daughter or her daughter's daughter. They are her close relatives. That is something I loathe.

¹⁸Don't marry your wife's sister and have sex with her while your wife is still alive. They will be hostile wives to one other.