“Teacher, Moses wrote for us: ‘If a man’s brother dies and leaves a wife but no children, that man must marry the widow and father children for his brother.’
For Herod himself had sent men, arrested John, and bound him in prison on account of Herodias, his brother Philip’s wife, because Herod had married her.
If brothers live together and one of them dies without having a son, the dead man’s wife must not remarry someone outside the family. Instead, her late husband’s brother must go to her, marry her, and perform the duty of a brother-in-law.