Numbers 3:27-28, 32, 38

From Kohath came the family of the Amramites, the family of the Izharites, the family of the Hebronites, and the family of the Uzzielites; these were the families of the Kohathites. According to the number of all the males, from a month old and above, there were eight thousand six hundred keeping charge of the sanctuary.

And Eleazar the son of Aaron the priest was to be chief over the leaders of the Levites, with oversight of those who kept charge of the sanctuary.

Moreover those who were to camp before the tabernacle on the east, before the tabernacle of meeting, were Moses, Aaron, and his sons, keeping charge of the sanctuary, to meet the needs of the children of Israel; but the outsider who came near was to be put to death.