All the men who were numbered of the Levites, whom Moses and Aaron and the leaders of Israel counted by their families (clans) and by their fathers’ households,
as well as the priests who were registered genealogically according to their fathers’ households, and the Levites from twenty years old and upward, by their duties and by their divisions.
These are the men who were numbered of the families of the sons of Merari, whom Moses and Aaron numbered in accordance with the commandment of the Lord through Moses.
from thirty years and upward even to fifty years old, everyone who could enter to do the work of service and the work of carrying in the Tent of Meeting (tabernacle);