Deuteronomy 25:3-7

He may have him beaten forty times, but not more, so that he does not have him beaten with many more lashes than these, and that your brother does not become contemptible in your eyes.

“You shall not muzzle the ox while it is threshing.

“When brothers live together, and one of them dies and has no son, the wife of the deceased shall not be married outside the family to a strange man. Her husband’s brother shall have relations with her and take her to himself as his wife, and perform the duty of a husband’s brother to her.

It shall then be that the firstborn to whom she gives birth shall assume the name of his father’s deceased brother, so that his name will not be wiped out from Israel.

But if the man does not desire to take his brother’s widow, then his brother’s widow shall go up to the gate to the elders, and say, ‘My husband’s brother refuses to establish a name for his brother in Israel; he is not willing to perform the duty of a husband’s brother to me.’