Leviticus 20:19-21

Verse

19 You must not have sexual relations with the sister of your mother or your father, for it is exposing one’s own kin; both shall bear their iniquity. 20 If a man lies with his uncle’s wife, he has uncovered the nakedness of his uncle. They will bear their sin; they shall die childless. 21 If a man marries his brother’s wife, it is an act of impurity. He has uncovered the nakedness of his brother; they shall be childless. (BSB)