Leviticus 20:12
"If a man has sexual relations with his daughter-in-law, the two are to be put to death. They've committed a repulsive act. Their guilt will remain their responsibility.
Leviticus 18:15
"You are not to expose the nakedness of your daughter-in-law. She's the wife of your son. You are not to have sexual relations with her.
Leviticus 18:23
"You are not to present yourself to an animal in order to have sexual relations with it and by doing so to defile yourself. A woman is not to present herself to an animal to have sexual relations with it. It's detestable.
Genesis 38:16
So on the way, he turned aside, approached her, and said, "Come on! Let's have some sex!" But he didn't realize that he was talking to his own daughter-in-law. "What will you give me," she asked, "in order to have sex with me?"
Genesis 38:18
Then he asked, "What pledge do you want me to give you?"
Deuteronomy 27:23
""Cursed is the one who has sexual relations with his mother-in-law.' "Then all the people are to respond by saying, "Amen!'