Where it appears

• Deut 25:5If brothers dwell together, and one of them dies, and has no son, the wife of the dead shall not be married outside to a stranger. Her husband’s brother shall go in to her, and take her as his wife, and perform the duty of a husband’s brother to her.
• Deut 25:7If the man doesn’t want to take his brother’s wife, then his brother’s wife shall go up to the gate to the elders, and say, “My husband’s brother refuses to raise up to his brother a name in Israel. He will not perform the duty of a husband’s brother to me.”