Numbers 7:7

Two wagons and four oxen he gave unto the sons of Gershon
The eldest son of Levi:

according to their service;
which was to bear and take care of the curtains, coverings, hangings and rails of the tabernacle; and which, when carrying from place to place, it was proper they should be covered from being exposed to rain and dust; and being so many as they were, must be heavy, burdensome, and cumbersome, and therefore two wagons, with two yoke of oxen, were given them, to ease them.