because their duty was to help the sons of Aharon in the service of the House of יהוה, in the courtyards and in the rooms, in the cleansing of all that was set-apart, and the work of the service of the House of Elohim,
and that they should guard the duty of the Tent of Meeting, the duty of the set-apart place, and the duty of the sons of Aharon their brothers in the service of the House of יהוה.