15 "If a man has two wives , the one loved and the other unloved , and both the loved and the unloved have borne him sons , if the firstborn son belongs to the unloved ,

Matthew Henry's Commentary on Deuteronomy 21:15

Commentary on Deuteronomy 21:15-17

(Read Deuteronomy 21:15-17)

This law restrains men from disinheriting their eldest sons without just cause. The principle in this case as to children, is still binding to parents; they must give children their right without partiality.