Genesis 38:8, 11, 26

Then Judah said to Er’s brother Onan, “Go and marry Tamar, as our law requires of the brother of a man who has died. You must produce an heir for your brother.”

Then Judah said to Tamar, his daughter-in-law, “Go back to your parents’ home and remain a widow until my son Shelah is old enough to marry you.” (But Judah didn’t really intend to do this because he was afraid Shelah would also die, like his two brothers.) So Tamar went back to live in her father’s home.

Judah recognized them immediately and said, “She is more righteous than I am, because I didn’t arrange for her to marry my son Shelah.” And Judah never slept with Tamar again.