Deuteronomy 25:5-10

⁵ "If brothers dwell together, and one of them dies and has no son, the wife of the dead shall not be married outside the family 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. ⁶ And the first son whom she bears shall succeed to the name of his brother who is dead, that his name may not be blotted out of Israel. ⁷ And if the man does not wish 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 perpetuate his brother's name in Israel; he will not perform the duty of a husband's brother to me.' ⁸ Then the elders of his city shall call him, and speak to him: and if he persists, saying, 'I do not wish to take her,' ⁹ then his brother's wife shall go up to him in the presence of the elders, and pull his sandal off his foot, and spit in his face; and she shall answer and say, 'So shall it be done to the man who does not build up his brother's house.' ¹⁰ And the name of his house shall be called in Israel, The house of him that had his sandal pulled off.