Genesis 38:8

The duty of a husband’s brother forms part of Moses’ law. (See Deuteronomy 25:5-6.) It is important in Ruth 3:1-22. We read about it in Mark 12:18-23. But this chapter (chapter 38) shows that the duty was much older than Moses’ law. The duty was this. A married man dies and he has no son. His wife is still alive. The dead man’s brother has a duty that he must have sex with the wife. If there is no brother, the dead man’s nearest relative has the duty. Their son is called the son of the dead man.

The reason for the duty was this. It was important to people in those times that they had *descendants. (See God’s *command to increase in Genesis 1:28.) If a man died without *descendants, his brother should give him *descendants. They were not his own *descendants, but they were *descendants of a close relative. And they were called his *descendants.