Remember that Levi, son of Jacob, himself had three sons: Gershom, Kohath, and Merari. As Israel moves from a tabernacle system of worship to a temple system, the work of each of these Levite families will change. The descendants of Kohath and Merari will be to assist the priests in their duties, and to act as gatekeepers for the temple. Gatekeepers served as a temple security force, maintaining the temple’s holiness, and protecting it from thieft and illegal entry into sacred areas.
The descendants of Kohath and Gershon served as keepers of the treasury. The Gershonites kept the temple treasury. The Kohathites kept David’s treasury. A first-rate kingdom would require a first-rate organization. As you read this, the impression you are supposed to get is that’s precisely what David is creating.
Israel was the Kingdom of God on earth then, and to achieve the glory God had planned for her, she needed purposeful organization and leadership. The same is true of the Kingdom of God today, the Church. It will never be what God has called it to be, nor achieve what God has demanded she achieve, without leaders who give it their attention.
One final note on this section: notice how closely David (the king) works with the priests, paving the way for the day when the monarchy and the priesthood would be one. Jesus is now both High Priest and King, and we as Christians serve as priests, and the royal family.