Leviticus 20:20-23

²⁰And if a man has sex relations with the wife of his father's brother, he has put shame on his father's brother: their sin will be on them; till the day of their death they will have no children.

²¹And if a man takes his brother's wife, it is an unclean act; he has put shame on his brother; they will have no children.

²²So then, keep my rules and my decisions and do them, so that the land which I am giving you as your resting-place may not violently send you out again.

²³And do not keep the rules of the nations which I am driving out before you; for they did all these things, and for that reason my soul was turned against them.