Numbers 4:22-24

Young's Literal Translation

²² `Take up the sum of the sons of Gershon also by the house of their fathers, by their families;

²³ from a son of thirty years and upward, till a son of fifty years thou dost number them, every one who is going in to serve the host, to do the service in the tent of meeting.

²⁴ `This [is] the service of the families of the Gershonite, to serve -- and for burden,