Edition 8 Then Judah said to Onan, “Go in to your brother’s wife and perform the duty of a brother-in-law to her; raise up offspring for your brother.” 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. The New Oxford Annotated Bible with Apocrypha: New Revised Standard Version 5th Edition 8 Then Judah said to Onan, “Go in to your brother’s wife and perform the duty of a brother-in-law to her; raise up offspring for your brother.” 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. The Jewish Study Bible: Second Edition 2nd Edition 8 Then Judah said to Onan, "Join with your brother's wife and do your duty by her as a brother-in-law: and provide offspring for your brother." 9 But Onan, knowing that the seed would not count as his, let it go to waste whenever he joined with his brother's wife, so as not to provide offspring for his brother. 10 What he did was displeasing to the Lord, and He took his life also. After Yahweh slew Onan's oldest brother Er, Onan's father Judah told him to fulfill his duty as a brother-in-law to his brother Er by entering into a levirate marriage with his brother's widow Tamar to give her offspring. Religion professor Tikva Frymer-Kensky has pointed out the economic repercussions of a levirate marriage: any son born to Tamar would be deemed the heir of the deceased Er and could claim the firstborn's double share of an inheritance. However, if Er were childless or only had daughters, Onan would have inherited as the oldest surviving son. When Onan had sex with Tamar, he withdrew before he ejaculated and "spilled his seed on the ground" thus committing coitus interuptus, since any child born would not legally be considered his heir. The next statement in the Bible says that Onan displeased Yahweh,