Deuteronomy 25:5-7

5When brothers live together and one of them dies without having a son, his widow must not marry outside the family. Her husband’s brother must marry her and sleep with her. He must do his duty as her brother-in-law.

6Then the first son she has will carry the dead brother’s name so that his name won’t die out in Israel.

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.”