Genesis 38:9-11

International Standard Version

⁹ But Onan knew that the offspring wouldn’t be his own heir, so whenever he had sexual relations with his brother’s wife, he would spill his semen on the ground to avoid fathering offspring for his brother. ¹⁰ The Lord considered what Onan was doing to be evil, so he put him to death, too.

¹¹ After this, Judah told his daughter-in-law Tamar, “Go live as a widow in your father’s house until my son Shelah grows up.” But he was really thinking, “…otherwise, Shelah^[a] might die like his brothers.” So Tamar left and lived in her father’s house.