Numbers 4:37-39

Wycliffe Bible

³⁷ This is the number of the people of Kohath, which entereth into the tabernacle of [the] bond of peace; Moses and Aaron numbered these, by the word of the Lord, by the hand of Moses. (This is the number of the people of Kohath, who served in the Tabernacle of the Covenant; Moses and Aaron listed them, obeying the word of the Lord, spoken by Moses.)

³⁸ And the sons of Gershon were numbered, by the kindreds and houses of their fathers,

³⁹ from thirty years and above unto fifty years, all that enter that they serve in the tabernacle of [the] bond of peace; (from thirty years of age up to fifty years old, all who entered to serve in the Tabernacle of the Covenant;)