'Firstborn Son' in the Bible

If a man have two wives, the one beloved, and the other hated, and they have borne him children, both the beloved and the hated; and if the firstborn son be hers who was hated;

and his firstborn son Abdon, and Zur, and Kish, and Baal, and Ner, and Nadab,

and his firstborn son Abdon, and Zur, and Kish, and Baal, and Ner, and Nadab,