Numbers 4:5-6, 15

When the Israelites are ready to move, Aaron and his sons must go into the Holy Tent, take down the curtain, and cover the Ark of the Agreement with it. Over this they must put a covering made from fine leather, then spread the solid blue cloth over that, and put the poles in place.

“When the Israelites are ready to move, and when Aaron and his sons have covered the holy furniture and all the holy things, the Kohathites may go in and carry them away. In this way they won’t touch the holy things and die. It is the Kohathites’ job to carry the things that are in the Meeting Tent.