Genesis 38:6-8

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

7But Er, Judah’s firstborn, was wicked in the LORD ’s sight; so the LORD put him to death. 8Then Judah said to Onan, “Sleep with your brother’s wife and fulfill your duty to her as a brother-in-law to raise up offspring for your brother.”