Deuteronomy 25:7-9

71But if the man does not desire to take his brother’s widow, then his brother’s widow shall go up to the gate to the elders, and say, ‘My husband’s brother refuses to establish a name for his brother in Israel; he is not willing to perform the duty of a husband’s brother to me.’

8Then the elders of his city shall summon him and speak to him. And if he persists and says, ‘I do not desire to take her,’

92then his brother’s widow shall come up to him in the sight of the elders, and pull his sandal off his foot and 3spit in his face; and she shall 4declare, ‘This is what is done to the man who does not build up his brother’s house!’