Numbers 3:32

And Eleazar the son of Aaron the priest
Who was of the first of these families, the Amramites:

[shall be] chief over the chief of the Levites;
over the three chiefs of the three houses of the Levites, who were Eliasaph the son of Lael, the chief of the Gershonites; and Elizaphan the son of Uzziel, the chief of the Kohathites; and Zuriel the son of Abihail, the chief of the Merarites:

[and have] the oversight of them that keep the charge of the
sanctuary;
the Kohathites, who had the care of the things belonging to the holy and most holy places; and these were particularly under the inspection of Eleazar, because they were things the priests had a, special concern in; see ( Numbers 4:32 ) .