Genesis 38:8

4She conceived again, and bore a son; and she named him Onan.

5She yet again bore a son, and named him Shelah. He was at Chezib when she bore him.

6Judah took a wife for Er, his firstborn, and her name was Tamar.

7Er, Judah’s firstborn, was wicked in the LORD’s sight. So the LORD killed him.

8Judah said to Onan, “Go in to your brother’s wife, and perform the duty of a husband’s brother to her, and raise up offspring for your brother.”

9Onan knew that the offspring wouldn’t be his; and when he went in to his brother’s wife, he spilled his semen on the ground, lest he should give offspring to his brother.

10The thing which he did was evil in the LORD’s sight, and he killed him also.

11Then Judah said to Tamar, his daughter-in-law, “Remain a widow in your father’s house, until Shelah, my son, is grown up;” for he said, “Lest he also die, like his brothers.” Tamar went and lived in her father’s house.

12After many days, Shua’s daughter, the wife of Judah, died. Judah was comforted, and went up to his sheep shearers to Timnah, he and his friend Hirah, the Adullamite.