Numbers 4:5 "When the camp sets out, Aaron and his sons shall go in and they shall take down the veil of the screen and cover the ark of the testimony with it;

Numbers 4:15 "When Aaron and his sons have finished covering the holy objects and all the furnishings of the sanctuary, when the camp is to set out, after that the sons of Kohath shall come to carry them, so that they will not touch the holy objects and die. These are the things in the tent of meeting which the sons of Kohath are to carry.

Numbers 7:9 But he did not give any to the sons of Kohath because theirs was the service of the holy objects, which they carried on the shoulder.

Deuteronomy 10:8 At that time the LORD set apart the tribe of Levi to carry the ark of the covenant of the LORD, to stand before the LORD to serve Him and to bless in His name until this day. (NASB ©1995)