Numbers 18:1

And the Lord said unto Aaron— God, having by the foregoing miracles vindicated the honour and authority of the priesthood, now lets Aaron know, probably by the hand of Moses, the importance of his office, wherein he was to behave with great care and circumspection; and withal he again declares the duty of the Levites, as distinct from that of the priests, from Numbers 18:1 to Numbers 18:8 and from thence proceeds to state what maintenance he had settled upon both for their encouragement in doing their duty. The bearing the iniquity of the sanctuary, and of the priesthood, means, that it should be upon them to bear the punishment of any profanations, either of the one, or the other, through their neglect.