Numbers 4:28-30

Authorized (King James) Version

²⁸ This is the service of the families of the sons of Gershon in the tabernacle of the congregation: and their charge shall be under the hand of Ithamar the son of Aaron the priest.

²⁹ As for the sons of Merari, thou shalt number them after their families, by the house of their fathers; ³⁰ from thirty years old and upward even unto fifty years old shalt thou number them, every one that entereth into the service, to do the work of the tabernacle of the congregation.