These were the descendants of Levi according to their families, that is, the leaders of families as counted and individually listed who carried out assigned tasks in the Lord’s temple and were twenty years old and up.
He gave him the regulations for the divisions of priests and Levites, for all the assigned responsibilities within the Lord’s temple, and for all the items used in the service of the Lord’s temple.
from thirty years old and upward to fifty years old, everyone who entered to do the work of service and the work of carrying relating to the tent of meeting –