Numbers 4:15
"And when Aaron and his sons have made an end of covering the sanctuary, and all the vessels of the sanctuary, as the camp is to set forward; after that, the sons of Kohath shall come to bear it: but they shall not touch any holy thing, lest they die. These things are the burden of the sons of Kohath in the tabernacle of the congregation."
Cross References (ranked by relevance)
But unto the sons of Kohath he gave none: because the service of the sanctuary belonging unto them was that they should bear upon their shoulders.
And Moses wrote this law, and delivered it unto the priests the sons of Levi, which bare the ark of the covenant of the LORD, and unto all the elders of Israel.
And the Kohathites set forward, bearing the sanctuary: and the other did set up the tabernacle against they came.
And he smote the men of Bethshemesh, because they had looked into the ark of the LORD, even he smote of the people fifty thousand and threescore and ten men: and the people lamented, because the LORD had smitten many of the people with a great slaughter.
Then David said, None ought to carry the ark of God but the Levites: for them hath the LORD chosen to carry the ark of God, and to minister unto him for ever.
And it was so, that when they that bare the ark of the LORD had gone six paces, he sacrificed oxen and fatlings.
And the children of the Levites bare the ark of God upon their shoulders with the staves thereon, as Moses commanded according to the word of the LORD.
And thou shalt set bounds unto the people round about, saying, Take heed to yourselves, that ye go not up into the mount, or touch the border of it: whosoever toucheth the mount shall be surely put to death:
But those that encamp before the tabernacle toward the east, even before the tabernacle of the congregation eastward, shall be Moses, and Aaron and his sons, keeping the charge of the sanctuary for the charge of the children of Israel; and the stranger that cometh nigh shall be put to death.
And when the tabernacle setteth forward, the Levites shall take it down: and when the tabernacle is to be pitched, the Levites shall set it up: and the stranger that cometh nigh shall be put to death.
For the priests which bare the ark stood in the midst of Jordan, until everything was finished that the LORD commanded Joshua to speak unto the people, according to all that Moses commanded Joshua: and the people hasted and passed over.