2 Chronicles 23:6

But let none come into the house of the Lord, the inner Temple, the Sanctuary proper with its court, save the priests and they that minister of the Levites, namely, in assisting in the offering of sacrifices; they shall go in, for they are holy, set apart especially for this duty; but all the people shall keep the watch of the Lord, behaving in a manner which would be in full accordance with all the precepts of the Lord.