Numbers 4:5-6, 15

When the camp is to set out, Aaron and his sons shall go in and take down the veil of the screen and cover the ark of the testimony with it. Then they shall put on it a covering of goatskin and spread on top of that a cloth all of blue, and shall put in its poles.

And when Aaron and his sons have finished covering the sanctuary and all the furnishings of the sanctuary, as the camp sets out, after that the sons of Kohath shall come to carry these, but they must not touch the holy things, lest they die. These are the things of the tent of meeting that the sons of Kohath are to carry.