Leviticus 18:15
You must not have sexual intercourse with your daughter-in-law; she is your son's wife. You must not have intercourse with her.
Leviticus 20:12
If a man has sexual intercourse with his daughter-in-law, both of them must be put to death. They have committed perversion; their blood guilt is on themselves.
Genesis 38:26
Judah recognized them and said, "She is more upright than I am, because I wouldn't give her to Shelah my son." He did not have sexual relations with her again.
Ezekiel 22:11
One commits an abominable act with his neighbor's wife; another obscenely defiles his daughter-in-law; another violates his sister -- his father's daughter -- within you.
Genesis 38:18-19
He said, "What pledge should I give you?" She replied, "Your seal, your cord, and the staff that's in your hand." So he gave them to her and had sex with her. She became pregnant by him.