Leviticus 20:20-22

²⁰Whosoever shall lie with his near kinswoman, has uncovered the nakedness of one near akin to him: they shall die childless.

²¹Whoever shall take his brother’s wife, it is uncleanness; he has uncovered his brother’s nakedness; they shall die childless.

²²And keep ye all my ordinances, and my judgments; and ye shall do them, and the land shall not be aggrieved with you, into which I bring you to dwell upon it.