Deuteronomy 25:5-6

Webster(i) 5 If brethren shall dwell together, and one of them shall die and have no child, the wife of the dead shall not marry without to a stranger: her husband's brother shall go in to her, and take her to him for a wife, and perform the duty of a husband's brother to her. 6 And it shall be, that the first-born which she beareth, shall succeed in the name of his brother who is dead, that his name may not become extinct in Israel.