Leviticus 18:15; Leviticus 20:12

Leviticus 18:15

15 Thou shalt not uncover the nakedness of thy daughter in law: she is thy son's wife; thou shalt not uncover her nakedness.

Leviticus 20:12

12 And if a man lie with his daughter in law, both of them shall surely be put to death: they have wrought confusion; their blood shall be upon them.