Numbers 4:5-6, 15

When the camp prepares to journey, Aaron and his sons shall come, and they shall take down the covering veil and cover the ark of the Testimony with it. Then they shall put on it a covering of badger skins, and spread over that a cloth entirely of blue; and they shall insert its poles.

And when Aaron and his sons have finished covering the sanctuary and all the furnishings of the sanctuary, when the camp is set to go, then the sons of Kohath shall come to carry them; but they shall not touch any holy thing, lest they die. “These are the things in the tabernacle of meeting which the sons of Kohath are to carry.