Numbers 4:42-45

Those listed of the clans of the sons of Merari, by their clans and their fathers’ houses, from thirty years old up to fifty years old, everyone who could come on duty, for service in the tent of meeting— those listed by clans were 3,200. This was the list of the clans of the sons of Merari, whom Moses and Aaron listed according to the commandment of the LORD by Moses.