These were numbered of the families of the Kohathites, all who did service in the Tent of Meeting (tabernacle), whom Moses and Aaron numbered according to 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);
According to the commandment of the Lord through Moses, they were numbered, each assigned to his work of serving and carrying. Thus they were numbered by him, just as the Lord had commanded Moses.