Leviticus 18:15
Never have sexual intercourse with your daughter-in-law. She is your son's wife. Never have sexual 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 done a disgusting thing and deserve to die.
Genesis 38:26
Judah recognized them and said: She is more righteous than I, since I would not give her to my son Shelah. He did not sleep with her again.
Ezekiel 22:11
Some commit adultery, and others seduce their daughters-in-law or their half sisters.
Genesis 38:18-19
What do you want? he asked. The ring on that cord around your neck, she replied. I also want the special walking stick you have with you. So he gave them to her. They slept together and she became pregnant.