Deuteronomy 25:7-9

7But if the man doesn’t want to marry his brother’s widow, she must go to the leaders of the city at the city gate. She must say, “My brother-in-law refuses to let his brother’s name continue in Israel. He doesn’t want to do his duty as my brother-in-law.”

8Then the leaders of the city must summon him and talk to him. If he persists in saying that he doesn’t want to marry her,

9his brother’s widow must go up to him in the presence of the leaders. She must take off one of his sandals and spit in his face. She must make this formal statement: “This is what happens to a man who refuses to continue his brother’s family line.”