Deuteronomy 25:7-9

7And if the man like not to take his brother’s wife, then his brother’s wife shall go up to the gate unto the elders, and say, My husband’s brother refuseth to raise up unto his brother a name in Israel; he will not perform the duty of a husband’s brother unto me. 8Then the elders of his city shall call him, and speak unto him: and if he stand, and say, I like not to take her; 9then shall his brother’s wife come unto him in the presence of the elders, and loose his shoe from off his foot, and spit in his face; and she shall answer and say, So shall it be done unto the man that doth not build up his brother’s house.