Leviticus 20:19-21

19You must not have sexual intercourse with your mother’s sister or your father’s sister, for it is exposing one’s own blood relative; both people will bear their iniquity.

20If a man sleeps with his aunt, he has violated the intimacy that belongs to his uncle; they will bear their guilt and die childless.

21If a man marries his brother’s wife, it is impurity. He has violated the intimacy that belongs to his brother; they will be childless.