Numbers 1:50
But thou shalt appoint the Levites over the tabernacle of testimony, and over all the vessels thereof, and over all things that belong to it: they shall bear the tabernacle, and all the vessels thereof; and they shall minister unto it, and shall encamp round about the tabernacle.
God specially appointed the Levites over the tabernacle of testimony and over all its vessels and all things belonging to it, rather than leaving the holy tabernacle to be borne, erected, and taken down indiscriminately by any tribe or person who chose. The work was assigned in an orderly way to people designated for it, because the sanctuary and its service were holy. This honor was given because they took no part in making and worshiping the golden calf and faithfully carried out His order against the idolaters.
Their appointed office was to bear the tabernacle and all its vessels, to minister unto it, to take down the sacred tent when the camp moved forward and set it up when a halting-place was reached, and to encamp round about the tabernacle. They dismantled it when Israel moved and set it up at each stopping place, both in camp and during travel, bearing it with the ark, the candlestick, and the other sacred articles of furniture. The work was divided among the three divisions descended from Levi's three sons: the Kohathites cared for the ark and the other furniture, the Merarites were in charge of the pillars, sockets, boards, and related parts, and the Gershonites were in charge of the curtains and hangings.
Their encampment positions were assigned, with Moses and Aaron in front of the tabernacle nearest to it, the Kohathites on the south, the Merarites on the north, and the Gershonites in the rear, and a special family of Levi was designated to bear the sacred ark in the midst. The Levites encamped round about the tabernacle while the hosts of Israel pitched at a distance from it. The sacred service and proximity were restricted to those God had appointed, with perfect order required in all journeyings and movements, so that no person of another tribe was allowed to come near on pain of death, and anyone who from curiosity or lack of order got out of his place, touched any part of the sanctuary or furniture, or even came near was to be put to death.
The appointed men were chosen because they could appreciate the sacredness of the work, and were to impress upon the people the special sacredness and holiness of the ark and all that pertained to the most holy place, so that all things pertaining to it would be looked upon with reverence. The arrangement teaches that every worker is to know his place and faithfully perform the special duties committed to him and let alone what another worker has been appointed to do. This honor made the Levites ambitious for still higher office and greater influence with the congregation, namely the priesthood, leading them with Korah to seek the priesthood.