Numbers 3:31-35

And their guard duty involved the ark, the table, the lampstand, the altars, the vessels of the sanctuary with which the priests minister, and the screen; all the service connected with these. And Eleazar the son of Aaron the priest was to be chief over the chiefs of the Levites, and to have oversight of those who kept guard over the sanctuary. To Merari belonged the clan of the Mahlites and the clan of the Mushites: these are the clans of Merari. Their listing according to the number of all the males from a month old and upward was 6,200. And the chief of the fathers’ house of the clans of Merari was Zuriel the son of Abihail. They were to camp on the north side of the tabernacle.