Deuteronomy 25:5-10

When brothers are living together and one of them dies without having had a son, the widow of the dead brother shall not marry a stranger from outside the family; her husband’s brother is to come to her and marry her and do the brother-in-law’s duty by her. The first son that she bears shall be named after her dead husband so his name won’t die out in Israel. But if the brother doesn’t want to marry his sister-in-law, she is to go to the leaders at the city gate and say, “My brother-in-law refuses to keep his brother’s name alive in Israel; he won’t agree to do the brother-in-law’s duty by me.” Then the leaders will call for the brother and confront him. If he stands there defiant and says, “I don’t want her,” his sister-in-law is to pull his sandal off his foot, spit in his face, and say, “This is what happens to the man who refuses to build up the family of his brother—his name in Israel will be Family-No-Sandal.”