Numbers 4:46-49

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, 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); the men that were numbered were 8,580. 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.