16 then it shall be in the day he wills what he has to his sons , he cannot e make the son of the loved the firstborn before e the son of the unloved , who is the firstborn .

Matthew Henry's Commentary on Deuteronomy 21:16

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.