In order to follow the rapid succession of events, it may be necessary to begin verse 8 by saying, for example, “After Er had died, Judah said to Onan….”

Go in to your brother’s wife: Go in to means have sexual relations with, which must be expressed in a way that is acceptable for public reading. See the case of Abraham and Hagar in 16.4, and of Jacob and his wives in 29.23, 30. In some languages your brother must be expressed as “your older brother.”

Perform the duty of a brother-in-law to her: Revised Standard Version‘s translation is a reasonable rendering of the Hebrew verb based on a word meaning brother of a widow’s dead husband. The verb form means to consummate the marriage (have sexual relations) with the dead brother’s widow. The purpose is to give Er’s widow children who will be acknowledged as the children of Er. These children will then have the inheritance rights of Er. This custom, called levirate marriage in English, was later incorporated into Hebrew law. See Deut 25.5-10. Deut 25.9-10 shows that it was a disgrace for a dead man’s living brothers to fail to have children with the widow of the deceased.

Raise up offspring for your brother states the purpose of Judah’s command to Onan. We may render this purpose “so that your brother may have descendants by means of you” or “in this way you will make it possible for your older brother to have descendants.”

In situations where people do not know about this custom, it may be desirable to make a direct reference to it in translation. In one case, for example, this is expressed as follows: “Your brother has died and had no children. Our custom is that you must take your brother’s wife and raise children for his name.” Another translation has “You should go and sleep with the wife of your dead brother, because that is what our law says. You must sleep with her to give her a baby for….”

Bible en français courant gives a translation model that some may find particularly helpful “Then Judah said to Onan: ‘You know your obligation as the next of kin to a deceased [brother]. You must give your brother descendants. Therefore marry his widow.’ ”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .