Numbers 4:28

²⁶And all the curtains of the court which were upon the tabernacle of witness, and the appendages, and all the vessels of service that they minister with they shall attend to.

²⁷According to the direction of Aaron and his sons shall be the ministry of the sons of Gershon, in all their ministries, and in all their works; and thou shalt take account of them by name in all things borne by them.

— Numbers 4:28 —

²⁹The sons of Merari according to their families, according to the houses of their lineage, take ye the number of them.

³⁰Take the number of them from five and twenty years old and upward until fifty years old, everyone that goes in to perform the services of the tabernacle of witness.