The covenant of priesthood must be made by sacrifice, as well as other covenants, Psa 50:5. And thus Christ was consecrated by the sacrifice of himself, once for all. Sacrifices of each kind must be offered for the priests, that they might with the more tenderness and concern offer the gifts and sacrifices of the people, with compassion on the ignorant, and on those that were out of the way, not insulting over those for whom sacrifices were offered, remembering that they themselves had had sacrifices offered for them, being compassed with infirmity. 1. A bullock, the largest sacrifice, was offered for a sin-offering (Lev 8:14), that hereby atonement might be made, and they might not bring any of the guilt of the sins of their former state into the new character they were now to put on. When Isaiah was sent to be a prophet, he was told to his comfort, Thy iniquity is taken away, Isa 6:7. Ministers, that are to declare the remission of sins to others, should give diligence to get it made sure to themselves in the first place that their own sins are pardoned. Those to whom is committed the ministry of reconciliation must first be reconciled to God themselves, that they may deal for the souls of others as for their own. 2. A ram was offered for a burnt-offering, Lev 8:18-21. By this they gave to God the glory of this great honour which was now put upon them, and returned him praise for it, as Paul thanked Christ Jesus for putting him into the ministry, Ti1 1:12. They also signified the devoting of themselves and all their services to the honour of God. 3. Another ram, called the ram of consecration, was offered for a peace-offering, Lev 8:22, etc. The blood of it was part put on the priests, on their ears, thumbs, and toes, and part sprinkled upon the altar; and thus he did (as it were) marry them to the altar, upon which they must all their days give attendance. All the ceremonies about this offering, as those before, were appointed by the express command of God; and, if we compare this chapter with Ex. 29, we shall find that the performance of the solemnity exactly agrees with the precept there, and in nothing varies. Here, therefore, as in the account we had of the tabernacle and its vessels, it is again and again repeated, As the Lord commanded Moses. And thus Christ, when he sanctified himself with his own blood, had an eye to his Father's will in it. As the Father gave me commandment so I do, Joh 14:31; Joh 10:18; Joh 6:38.

And Moses took - the blood - and sprinkled it upon Aaron, etc. - Thus we find that the high priest himself must be sprinkled with the blood of the sacrifice; and our blessed Lord, of whom Aaron was a type, was sprinkled with his own blood.
1. In his agony in the garden.
2. In his being crowned with thorns.
3. In the piercing of his hands and his feet. And,
4. In his side being pierced with the spear. All these were so many acts of atonement performed by the high priest.

And Moses took of the anointing oil, and of the blood which was upon the altar,.... Which was sprinkled upon the altar round about, Lev 8:24 and these two seem to be mixed together, since it follows:

and sprinkled it upon Aaron, &c. See Gill on Exo 29:21.

brought the other ram,--&c. After the sin offering and burnt offering had been presented on their behalf, this was their peace offering, by which they declared the pleasure which they felt in entering upon the service of God and being brought into close communion with Him as the ministers of His sanctuary, together with their confident reliance on His grace to help them in all their sacred duties.