John Calvin Commentary Leviticus 16:3

"Herewith shall Aaron come into the holy place: with a young bullock for a sin-offering, and a ram for a burnt-offering." — Leviticus 16:3 (ASV)

Thus shall Aaron come into the holy place. The rites and formality are now described:

1. That Aaron should put on the holy garments and wash his person.
2. That he should offer a bullock and ram for a burnt offering.
3. That he should take two goats from the people, one of which should be sent away alive, and the other slain in sacrifice.

We have stated elsewhere why the priests were to be dressed in garments different from others. This was because the mediator between God and men should be free from all impurity and stain. Since no mortal could truly provide this, a type was substituted for the reality, from which believers might learn that another Mediator was to be expected. This was also because the dignity of the sons of Aaron was only typical, and not true and substantial.

For whenever the priest stripped himself of his own garments and assumed those that were holy and separated from common use, it was equivalent to declaring openly that he represented another person.

But if this symbol were not sufficient, the ablution also taught that none of the sons of Aaron was the genuine propitiator. For how could he purify others, who himself required purification and openly confessed his own uncleanness? A third symbol was also added: for he who by a sacrifice of his own atoned for himself and his house, how was he capable of meriting God’s favor for others?

Thus, then, the holy fathers were reminded that, under the image of a mortal man, another Mediator was promised, who, for the reconciliation of the human race, should present Himself before God with perfect and more than angelical purity.

Besides, in the person of the priest, a spectacle of the corruption by which the whole human race is defiled, making it abominable to God, was exhibited to the people. For if the priest, chosen by God and graced with the sacred unction, was still unworthy on account of his uncleanness to come near the altar, what dignity could be found in the people?

And from this, very useful instruction is also derived for us today: namely, that when the question arises of how God is to be propitiated, we are not to look in various directions, because apart from Christ there is no purity and innocence that can satisfy the justice of God.