Genesis 38:8

Then Judah said to Onan, “Have sexual relations with ¹  your brother’s wife and fulfill the duty of a brother-in-law to her so that you may raise ²  up a descendant for your brother.” ³ 

Then Judah said to Onan, "Lie with your brother’s wife and fulfil your duty to her as a brother-in-law to produce offspring for your brother."

Then Judah said to Onan, "Go in to your brother’s wife, and perform your duty as a brother-in-law to her, and raise up offspring for your brother."

Then Judah said to Er’s brother Onan, "You must marry Tamar, as our law requires of the brother of a man who has died. Her first son from you will be your brother’s heir."

So Judah told Onan, "Go and sleep with your brother's widow; it's the duty of a brother-in-law to keep your brother's line alive."

Then Judah said to Onan, Go in to your brother’s wife and do what it is right for a husband’s brother to do; make her your wife and get offspring for your brother.

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."

And Judah said to Onan, "Go in to your brother’s wife and marry her, and raise up an heir to your brother."

Then Judah said to Onan, “Have sexual relations with ¹  your brother’s wife and fulfill the duty of a brother-in-law to her so that you may raise ²  up a descendant for your brother.” ³ 

¹ tn Heb “go to.” The expression is a euphemism for sexual intercourse.

² tn The imperative with the prefixed conjunction here indicates purpose.

³ sn Raise up a descendant for your brother. The purpose of this custom, called the levirate system, was to ensure that no line of the family would become extinct. The name of the deceased was to be maintained through this custom of having a child by the nearest relative. See M. Burrows, “Levirate Marriage in Israel,” JBL 59 (1940): 23-33.