Numbers 4:42-45

The men who were numbered of the sons of Merari, by their families (clans), by their fathers’ households, from thirty years and upward even to fifty years old, everyone who entered the service for work in the Tent of Meeting (tabernacle); the men who were numbered by their families were 3,200. 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.