Now these are the last words of David: The oracle of David the son of Jesse, the oracle of the man who was raised on high, the anointed of the God of Jacob, and the favorite psalmist of Israel:
These were the sons of Levi according to their fathers’ houses, the heads of the fathers’ houses as they were registered by the number of their names according to their head count, those doing the work for the service of the house of the Lord, from twenty years old and up.
because their duty was to help the sons of Aaron in the service of the house of the Lord, in the courts and in the chambers, with the purifying of all holy things, even the work of service of the house of God,
The registration of the priests was according to the house of their fathers and the Levites from twenty years and above, according to their duties and their divisions.