Deuteronomy 21:15-17·~1 min
Inheritance Rights of the Firstborn
If a man has sons by two wives and prefers one wife over the other, he may not transfer firstborn status to the favored wife's son. He must acknowledge the actual firstborn and give him the double share that belongs to him.
I15f a man has two wives, one beloved and the other unloved, and both bear him sons, but the unloved wife has the firstborn son, 16when that man assigns his inheritance to his sons he must not appoint the son of the beloved wife as the firstborn over the son of the unloved wife. 17Instead, he must acknowledge the firstborn, the son of his unloved wife, by giving him a double portion of all that he has. For that son is the firstfruits of his father’s strength; the right of the firstborn belongs to him.
Section summaryA father's affections must not reorder inheritance. If the firstborn belongs to the less loved wife, his status still stands, and he must receive the double portion that belongs to the firstborn.
Role in the chapterThis brief law protects family order from favoritism. In a chapter shaped by strong desires and harsh judgments, it insists that established right must hold against private preference.