7 But if the man does not want to take his brother's wife, then let his brother's wife go up to the gate to the elders, and say, 'My husband's brother refuses to raise up a name to his brother in Israel; he will not perform the duty of my husband's brother.'
Matthew Henry's Commentary on Deuteronomy 25:7
Commentary on Deuteronomy 25:5-12
(Read Deuteronomy 25:5-12)
The custom here regulated seems to have been in the Jewish law in order to keep inheritances distinct; now it is unlawful.