1 Chronicles 23:2-5, 24, 25-27

At the same time he brought together all the leaders of Israel, the priests, and the Levites. The Levites thirty years and older were counted; the total was thirty-eight thousand. David sorted them into work groups: “Twenty-four thousand are in charge of administering worship in the sanctuary; six thousand are officials and judges; four thousand are security guards; and four thousand are to serve in the orchestra, praising GOD with instruments that I have provided for praise.”

These are the sons of Levi twenty years and older, divided up according to families and heads of families and listed in the work groups that took care of the worship in the sanctuary of GOD.

David said, “Now that the GOD of Israel has given rest to his people and made Jerusalem his permanent home, the Levites no longer have to carry the Tabernacle and all the furniture required for the work of worship.” These last words of David referred only to Levites twenty years old and above.