The sons of Amram: Aaron, Moses and Miriam. And the sons of Aaron: Nadab, Abihu, Eleazar, and Ithamar.

The divisions of the descendants of Aaron were these: the sons of Aaron were Nadab, Abihu, Eleazar, and Ithamar.

But Nadab and Abihu died before their father and had no sons; therefore Eleazar and Ithamar served as priests.

David, with Zadok of the sons of Eleazar and Ahimelech of the sons of Ithamar, divided them according to their offices for their assigned duties.

Since there were more chief men found among the descendants of Eleazar than among the descendants of Ithamar [because of Eli’s misfortunes, and Saul’s massacre of the priests at Nob], they were divided in this way: sixteen heads of fathers’ households of the descendants of Eleazar and eight of the descendants of Ithamar, corresponding to their fathers’ households.

So they were divided by lot, one group with the other; for they were officers of the sanctuary and officers (high priests) of God, both from the descendants of Eleazar and from the descendants of Ithamar.

Shemaiah, the son of Nethanel the scribe, from the Levites, recorded them in the presence of the king, the officers, Zadok the priest, Ahimelech the son of Abiathar [the priest who escaped Saul’s massacre at Nob], and the heads of the fathers’ households of the priests and of the Levites; one father’s household taken for Eleazar and one taken for Ithamar.