'Firstborn Son' in the Bible

Ishmael's firstborn son was Nebaioth; the others were Kedar, Adbeel, Mibsam,

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

Mattithiah, a Levite, the firstborn son of Shallum the Korahite, was in charge of baking the bread for offerings.

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