Genesis 38:9-11

New Revised Standard Version, Anglicised

⁹ But since Onan knew that the offspring would not be his, he spilled his semen on the ground whenever he went in to his brother’s wife, so that he would not give offspring to his brother. ¹⁰ What he did was displeasing in the sight of the Lord, and he put him to death also. ¹¹ Then Judah said to his daughter-in-law Tamar, ‘Remain a widow in your father’s house until my son Shelah grows up’—for he feared that he too would die, like his brothers. So Tamar went to live in her father’s house.