Deuteronomy 21:17
17 But the first-born, son of the hated one, he doth acknowledge, to give to him a double portion of all that is found with him, for he 'is' the beginning of his strength; to him 'is' the right of the first-born.
Young's Literal Translation is in the public domain.
Matthew Henry's Commentary on Deuteronomy 21:17
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.