Genesis 38:7-9

New King James Version

⁷ But ^(A)Er, Judah’s firstborn, was wicked in the sight of the Lord, ^(B)and the Lord killed him. ⁸ And Judah said to Onan, “Go in to ^(C)your brother’s wife and marry her, and raise up an heir to your brother.” ⁹ But Onan knew that the heir would not be ^(D)his; and it came to pass, when he went in to his brother’s wife, that he emitted on the ground, lest he should give an heir to his brother.