If a married man dies without children, what must his brother do?
Have sex with and marry his dead brother's wife
If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not marry without unto a stranger: her husband's brother shall go in unto her,
and take her to him to wife, and perform the duty of an husband's brother unto her.
Deuteronomy 25:5
