1 Chronicles 24:3

3 Along with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, David organized them according to the appointed duties in their service.

1 Chronicles 24:3 Meaning and Commentary

1 Chronicles 24:3

And David distributed them
The posterities of Eleazar and Ithamar into certain classes or courses:

both Zadok of the sons of Eleazar, and Ahimelech of the sons of
Ithamar;
these were the two principal men of the respective families, the one was high priest, and the other "sagan" or deputy; or they both officiated as high priests alternately, until the one was removed in Solomon's time, and the other established alone. And now their brethren the priests, who were under each of these, are the persons David divided into classes:

according to their offices in their service:
to perform their office as priests in the service of the temple in their turns.

1 Chronicles 24:3 In-Context

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

2 But Nadab and Abihu died before their father, and had no sons; so Eleazar and Ithamar became the priests.

3 Along with Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, David organized them according to the appointed duties in their service.

4 Since more chief men were found among the sons of Eleazar than among the sons of Ithamar, they organized them under sixteen heads of ancestral houses of the sons of Eleazar, and eight of the sons of Ithamar.

5 They organized them by lot, all alike, for there were officers of the sanctuary and officers of God among both the sons of Eleazar and the sons of Ithamar.