1 Chronicles 24:3

3 With the help of Zadok and Ahimelech, David separated the priests into groups. Each group served in its appointed order and time. Zadok belonged to the family line of Eleazar. Ahimelech belonged to the family line of Ithamar.

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 Here are the groups of priests the sons of Aaron were separated into. The sons of Aaron were Nadab, Abihu, Eleazar and Ithamar.

2 But Nadab and Abihu died before their father did. They didn't have any sons. So Eleazar and Ithamar served as the priests.

3 With the help of Zadok and Ahimelech, David separated the priests into groups. Each group served in its appointed order and time. Zadok belonged to the family line of Eleazar. Ahimelech belonged to the family line of Ithamar.

4 More leaders were found among Eleazar's family line than among Ithamar's. So the priests were separated into their groups based on that fact. There were 16 family leaders from Eleazar's line. There were eight family leaders from Ithamar's line.

5 The priests were separated into their groups by using lots. That was the fair way to do it. The priests were officials of the temple and officials of God. They came from the family lines of Eleazar and Ithamar.