Numbers 4:4

¹⁹but do this to them, that they may live, and not die, when they approach the most holy things: Aaron and his sons shall go in and appoint everyone to his service and to his burden;

³⁴“It is like a man traveling to another country, having left his house and given authority to his servants, and to each one his work, and also commanded the doorkeeper to keep watch.

³⁰The prince of the fathers’ house of the families of the Kohathites shall be Elizaphan the son of Uzziel. ³¹Their duty shall be the ark, the table, the lamp stand, the altars, the vessels of the sanctuary with which they minister, the screen, and all its service.

³⁰you shall count them from thirty years old and upward even to fifty years old—everyone who enters on the service, to do the work of the Tent of Meeting.

²⁴“This is the service of the families of the Gershonites, in serving and in bearing burdens:

¹⁵“When Aaron and his sons have finished covering the sanctuary and all the furniture of the sanctuary, as the camp moves forward; after that, the sons of Kohath shall come to carry it; but they shall not touch the sanctuary, lest they die. The sons of Kohath shall carry these things belonging to the Tent of Meeting.