Genesis 38:7-9

Good News Translation

⁷ Er's conduct was evil, and it displeased the Lord, so the Lord killed him. ⁸ Then Judah said to Er's brother Onan, “Go and sleep with your brother's widow. Fulfill your obligation to her as her husband's brother, so that your brother may have descendants.” ⁹ But Onan knew that the children would not belong to him, so when he had intercourse with his brother's widow, he let the semen spill on the ground, so that there would be no children for his brother.