9 then shall his brother's wife come near to him before the eyes of the elders, and draw his sandal from his foot, and spit in his face, and shall answer and say, So shall it be done unto the man that will not build up his brother's house.

Matthew Henry's Commentary on Deuteronomy 25:9

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.