1 Chronicles 24:2-4

American Standard Version

² But Nadab and Abihu died before their father, and had no children: therefore Eleazar and Ithamar executed the priest’s office. ^3 [a]And David with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, divided them according to their ordering in their service. ⁴ And there were more chief men found of the sons of Eleazar than of the sons of Ithamar; and thus were they divided: of the sons of Eleazar there were sixteen, heads of fathers’ houses; and of the sons of Ithamar, according to their fathers’ houses, eight.