Genesis 38:3-7

38:3 She became pregnant and had a son. Judah named him Er. 38:4 She became pregnant again and had another son, whom she named Onan. 38:5 Then she had yet another son, whom she named Shelah. She gave birth to him in Kezib.

38:6 Judah acquired a wife for Er his firstborn; her name was Tamar. 38:7 But Er, Judah’s firstborn, was evil in the Lord’s sight, so the Lord killed him.