Leviticus 20:17; Leviticus 20:20

17 “ ‘If a man marries his sister, the daughter of either his father or his mother, and they have sexual relations, it is a disgrace. They are to be publicly removed from their people. He has dishonored his sister and will be held responsible.

20 “ ‘If a man has sexual relations with his aunt, he has dishonored his uncle. They will be held responsible; they will die childless.