Numbers 4:41-43

Young's Literal Translation

⁴¹ These [are] those numbered of the families of the sons of Gershon, every one who is serving in the tent of meeting, whom Moses and Aaron numbered by the command of Jehovah.

⁴² And those numbered of the families of the sons of Merari, by their families, by the house of their fathers,

⁴³ from a son of thirty years and upward even unto a son of fifty years, every one who is going in to the host, for service in the tent of meeting,