1 Chronicles 24:2-4

Young's Literal Translation

² and Nadab dieth, and Abihu, in the presence of their father, and they had no sons, and Eleazar and Ithamar act as priests.

³ And David distributeth them, and Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their office in their service;

⁴ and there are found of the sons of Eleazar more for heads of the mighty men than of the sons of Ithamar; and they distribute them: Of the sons of Eleazar, heads for a house of fathers, sixteen; and of the sons of Ithamar, for a house of their fathers, eight.