Numbers 4:5, commentary and pictures

When the camp set forward, Aaron and his sons were to come and take down the covering veil and cover the ark of the testimony with it before it was carried. The sacred ark was not to be handled or carried indiscriminately or by any tribe at its own discretion, but in precise and orderly fashion by designated, appointed people. This priestly task of covering the ark belonged to the sacred service and followed God's exact, ordered procedures for moving the sanctuary.

This covering and transport belonged to the Levites' assigned work of taking down and carrying the tabernacle and its sacred furnishings on the journey. The Kohathites were assigned care of the ark and the other furnishings, while the Levites took down and transported the sacred tent and its contents. The Levites were honored with this service of the tabernacle because they took no part in making and worshiping the golden calf and faithfully carried out God's order against the idolaters. Their office was to erect the tabernacle and camp around it while Israel camped at a distance, and when Israel journeyed to take down the tabernacle and carry the ark, the candlestick, and the other sacred articles of furniture.

The instructions taught Israel to treat the ark and everything connected with the sanctuary with reverence for their holiness, reflecting the care and reverence required for sacred duties. The ark represented Jehovah among His people, and it was always covered when removed from the sanctuary so that no curious eye could see it. Even the cherubim over the mercy seat were left unexposed, and its covering expressed its sacredness and the reverence due to it. Because God thus honored them, the Levites became ambitious for still higher office and greater influence with the congregation, joining the resolve to obtain the priesthood and the government.