2 So bring with you also your brothers of the tribe of Levi, your ancestral tribe, in order that they may be joined to you, and serve you while you and your sons with you are in front of the tent of the covenant. 3 They shall perform duties for you and for the whole tent. But they must not approach either the utensils of the sanctuary or the altar, otherwise both they and you will die. 4 They are attached to you in order to perform the duties of the tent of meeting, for all the service of the tent; no outsider shall approach you. 5 You yourselves shall perform the duties of the sanctuary and the duties of the altar, so that wrath may never again come upon the Israelites. 6 It is I who now take your brother Levites from among the Israelites; they are now yours as a gift, dedicated to the Lord, to perform the service of the tent of meeting.
Matthew Henry's Commentary on Numbers 18:2-6
Commentary on Numbers 18:1-7
(Read Numbers 18:1-7)
The people complained of their difficulty and peril in drawing near to God. God here gives them to understand, that the priests should come near for them. Aaron would see reason not to be proud of his preferment, when he considered the great care and charge upon him. Be not high-minded, but fear. The greater the trust of work and power that is committed to us, the greater danger there is of betraying that trust. This is a good reason why we should neither envy others' honours, nor desire high places.