Numbers 4:37-39

New King James Version

³⁷ These were the ones who were numbered of the families of the Kohathites, all who might serve in the tabernacle of meeting, whom Moses and Aaron numbered according to the commandment of the Lord by the hand of Moses.

³⁸ And those who were numbered of the sons of Gershon, by their families and by their fathers’ house, ³⁹ from thirty years old and above, even to fifty years old, everyone who entered the service for work in the tabernacle of meeting—