Genesis 38:6-8

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

7But 1Er, Judah’s firstborn, was evil in the sight of the Lord, so the Lord took his life.

8Then Judah said to Onan, “2Have relations with your brother’s wife and perform your duty as a brother-in-law to her, and raise up a 3child for your brother.”