¶ 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.
Jewish Publication Society of America Version (JPS1917) - Deuteronomy 25:5 >If brethren dwell together, and one of them die, and have no child, the wife of the dead shall not be married abroad unto one not of his kin; her husband's brother shall go in unto her, and take her to him to wife, and perform the duty of a husband's brother unto her.