You must not have sexual relations with your son's daughter or your daughter's daughter; their nakedness you shall not uncover, for they are your own flesh.
You shall not uncover the nakedness of your daughter-in-law; she is your son's wife; you shall not have intercourse with her.
And if a man lies carnally with his daughter-in-law, both of them shall surely be put to death; they have wrought confusion, perversion, and defilement; their blood shall be upon their own heads.
Then Judah said to Tamar, his daughter-in-law, Remain a widow at your father's house till Shelah my [youngest] son is grown; for he thought, Lest perhaps [if Shelah should marry her] he would die also, as his brothers did. So Tamar went and lived in her father's house.
He turned to her by the road and said, Come, let me have intercourse with you; for he did not know that she was his daughter-in-law. And she said, What will you give me that you may have intercourse with me?
1 Chronicles 2:4
Tamar, Judah's daughter-in-law, bore him Pharez and Zerah. All Judah's sons were five.
Then she arose with her daughters-in-law to return from the country of Moab, for she had heard in Moab how the Lord had visited His people in giving them food.
So she left the place where she was, her two daughters-in-law with her, and they started on the way back to Judah.
And may he be to you a restorer of life and a nourisher and supporter in your old age, for your daughter-in-law who loves you, who is better to you than seven sons, has borne him.
1 Samuel 4:19
Now his daughter-in-law, Phinehas' wife, was with child, about to be delivered. And when she heard that the ark of God was captured and that her father-in-law and her husband were dead, she bowed herself and gave birth, for her pains came upon her.
For the son dishonors the father, the daughter rises up against her mother, the daughter-in-law against her mother-in-law -- "a man's enemies are the men (members) of his own house.
For I have come to part asunder a man from his father, and a daughter from her mother, and a newly married wife from her mother-in-law -- "
They will be divided, father against son and son against father, mother against daughter and daughter against mother, mother-in-law against her daughter-in-law and daughter-in-law against her mother-in-law.