NET
8 Then Judah said to Onan, “Sleep with your brother’s wife and fulfill the duty of a brother-in-law to her so that you may raise up a descendant for your brother.”
Darby
8 Then Judah said to Onan, Go in to thy brother's wife, and fulfil to her the brother-in-law's duty, and raise up seed to thy brother.
KJV
8 And Judah said unto Onan, Go in unto thy brother's wife, and marry her, and raise up seed to thy brother.