“Teacher,” they began, “Moses gave us a law that if a married man dies leaving a wife without children, then his brother should marry the widow and have children for his dead brother.
Then Judah told his daughter-in-law Tamar, “Go to your father's house and live there as a widow until my son Shelah grows up.” For he thought, “Maybe he'll die too, just like his brothers.” So Tamar went and stayed in her father's house.
Judah recognized them right away and said, “She has honored the law more than I have, because I didn't give her in marriage to my son Shelah.” He didn't sleep with Tamar again.