Genesis 38:9-11

But Onan knew that the heir would not be 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. And the thing which he did displeased the LORD; therefore He killed him also. Then Judah said to Tamar his daughter-in-law, “Remain a widow in your father’s house till my son Shelah is grown.” For he said, “Lest he also die like his brothers.” And Tamar went and dwelt in her father’s house.