17 For all the first-born among the children of Israel are mine, both man and beast: on the day that I smote all the first-born in the land of Egypt I sanctified them for myself. 18 And I have taken the Levites instead of all the first-born among the children of Israel. 19 And I have given the Levites as a gift to Aaron and to his sons from among the children of Israel, to do the service of the children of Israel in the tent of meeting, and to make atonement for the children of Israel; that there be no plague among the children of Israel, when the children of Israel come nigh unto the sanctuary.
Matthew Henry's Commentary on Numbers 8:17-19
Commentary on Numbers 8:5-26
(Read Numbers 8:5-26)
Here we have directions for the solemn ordination of the Levites. All Israel must know that they took not this honour to themselves, but were called of God to it; nor was it enough that they were distinguished from others. All who are employed for God, must be dedicated to him, according to the employment. Christians must be baptized, ministers must be ordained; we must first give ourselves unto the Lord, and then our services. The Levites must be cleansed. They must be clean that bear the vessels of the Lord. Moses must sprinkle the water of purifying upon them. This signifies the application of the blood of Christ to our souls by faith, that we may be fit to serve the living God. God declares his acceptance of them. All who expect to share in the privileges of the tabernacle, must resolve to do the service of the tabernacle. As, on the one hand, none of God's creatures are his necessary servants, he needs not the service of any of them; so none are merely honorary servants, to do nothing. All whom God owns, he employs; angels themselves have their services.