Genesis 38:8

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 

[38:8]  ¹ tn Heb “go to.” The expression is a euphemism for sexual intercourse.

[38:8]  ² tn The imperative with the prefixed conjunction here indicates purpose.

[38:8]  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.