Deuteronomy 25:5-7

EJ2000(i) 5 ¶ When brethren dwell together and one of them dies and has no child, the wife of the dead shall not marry outside unto a stranger; 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. 6 And it shall be that the firstborn which she bears shall be raised up in the name of his brother who is dead that his name be not blotted out of Israel. 7 And if the man does not desire to take his brother’s wife, then let his brother’s wife go up to the gate unto the elders and say, My husband’s brother refuses to raise up unto his brother a name in Israel; he will not perform the duty of my husband’s brother.