Genesis 38:9-11

New Catholic Bible

⁹ But Onan knew that the child would not have been considered to be his own. Every time that he slept with the wife of his brother, he spilled his seed on the ground so that he would not have to give his brother a son.^{[a] 10} This greatly displeased the Lord, and the Lord caused him to die, too.

¹¹ Thereupon Judah said to his daughter-in-law Tamar, “Return to the house of your father as a widow until my son Shelah will have grown up.” For he thought, “Let him not die like his brothers.” So Tamar went and returned to the house of her father.