Genesis 38:6-9

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, “2Go in to your brother’s wife, and perform your duty as a brother-in-law to her, and raise up 3offspring for your brother.”

9Onan knew that the 45offspring would not be his; so when he went in to his brother’s wife, he 6wasted his seed on the ground in order not to give 7offspring to his brother.