Deuteronomy 25:4-6

Thou shalt not muzzle the ox when he treadeth out {the corn}. {treadeth...: Heb. thresheth} 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. {her husband's...: or, her next kinsman} And it shall be, {that} the firstborn which she beareth shall succeed in the name of his brother {which is} dead, that his name be not put out of Israel.