Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Num 18:1-7) The charge of the priests and Levites.
(Num 18:8-19) The priests' portion.
(Num 18:20-32) The Levites' portion.
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.
All believers are spiritual priests, and God has promised to take care of them. Godliness has the promise of the life that now is. And from the provision here made for the priests, the apostle shows that it is the duty of Christian churches to maintain their ministers. Scandalous maintenance makes scandalous ministers. The priests were to be wholly devoted to their ministry, not diverted from it, or disturbed in it, by worldly care or business. Also, that they might be examples of living by faith, not only in God's providence, but in his ordinances. The best should be offered for the first-fruits unto the Lord. Those who think to save, by putting God off with the refuse, deceive themselves, for God is not mocked.
As Israel was a people not to be numbered among the nations, so Levi was a tribe to be distinguished from the rest. Those who have God for their Inheritance and their Portion for ever, ought to look with holy contempt and indifference upon the possessions of this world. The Levites were to give God his dues out of their tithes, as well as the Israelites out of their increase. See, in Num 18:31, the way to have comfort in all our worldly possessions, so as to bear no sin by reason of them. 1. We must be sure that what we have is got honestly and in the service of God. That meat is best eaten which is first earned; but if any will not work, neither shall he eat, Th2 3:10. 2. We must be sure that God has his dues out of it. We have the comfort of our substance, when we have honoured the Lord with it. Ye shall bear no sin by reason of it, when ye have heaved the best from it. We should give alms of such things as we have, that all may be holy and comfortable to us.