Instead, 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.
Jewish Publication Society of America Version (JPS1917) - Deuteronomy 21:17 >but he shall acknowledge the first-born, the son of the hated, by giving him a double portion of all that he hath; for he is the first-fruits of his strength, the right of the first-born is his.