Numbers 4:23-25

Young's Literal Translation

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,

²⁵ and they have borne the curtains of the tabernacle, and the tent of meeting, its covering, and the covering of the badger [skin] which [is] on it above, and the vail at the opening of the tent of meeting,