And every priest stands ministering daily and offering repeatedly the same sacrifices, which can never take away sins. But this Man, after He had offered one sacrifice for sins forever, sat down at the right hand of God. – Hebrews 10:11,12

We observe that as there were many priests, so there were many sacrifices for sins. The sacrifice was offered once, but sin was not put away and therefore had to be offered again. The great day of atonement came every year, wherein sin was afresh brought to remembrance. There was a day of atonement last year, but the people are unforgiven, and there must be a day of atonement this year; and when that day is over and the priest has come forth in his holy and beautiful apparel, with the breastplate gleaming in the light of God, Israel may rejoice for a while but there is one thought that will sadden her; there must be an atonement day next year, for sin still remaineth upon Israel, notwithstanding all that the house of Aaron can do by all their sacrifices. Yea, and moreover, remembrance of sin was of necessity made every day. There was the lamb for the morning, the innocent victim was slaughtered and burned; but the morning sacrifice did not put away the day’s sin, for as the sun began to descend in the west another victim must be brought, and so on each morning and each night, victim, victim, victim, sacrifice, sacrifice, sacrifice, because the expiation was always incomplete. But our blessed Lord, “the Lamb of God that taketh away the sins of the world,” was sacrificed but once, and that one sacrifice hath completed His expiatory work. In very truth His was a sacrifice of nobler name and richer blood than theirs.

How could the blood of bulls and of goats put away sin? What conceivable connection can there be, except in symbol, between the death pangs of a beast and the sin of a man before God? The principle of substitution was by the legal sacrifices clearly set forth, but that was all; those offerings did not and could not provide the actual substitute…Where but in the Christ of God could a propitiation be found? Where else is there one who could in our nature make recompense to the injured law of God?

The Only Atoning Priest by C. H. Spurgeon

And every priest stands ministering daily and offering repeatedly the same sacrifices, which can never take away sins. But this Man, after He had offered one sacrifice for sins forever, sat down at the right hand of God… – Hebrews 10:11,12

In that old dispensation, the first point mentioned in the text is that there were many priests. “For every priest standeth”—implying that there were several. There were many priests at the same time—the sacrifices of the temple were too numerous to have been all of them performed by one man: all the descendants of Aaron were set apart to this work, and even then they required the aid of the Levites in certain inferior duties. And as there were many priests at one time, so there were many in succession. As a priest died, he was succeeded by his sons. By reason of infirmity, they were not able to continue in their office even through the whole of their lifetime; there was a certain period at which they were commanded to surrender their office to younger men. By reason of mortality the priesthood was perpetually changing; one high priest died, and was succeeded by another. Now the reason for the existence of many priests was this, that no one priest had accomplished the work of expiation. The good man has gone to his fathers and offered up the last of the morning lambs—but the morning lambs must still be offered. The high priest is dead, and there shall be no more opportunity for him to enter into that which is within the veil, but there must be a new high priest appointed, for the work is not finished. There were many priests, and as one generation passed away, another inherited the mitre. Now, herein is the glory of Christ that He is but one, and to this our attention is called by the apostle; that whereas there were many priests, and the sacrifices were hereby proved to be incomplete, since others had to take up the work; here is but one priest for ever, and He has finished His work, and therefore sits down at the right hand of God.

The Only Atoning Priest by C. H. Spurgeon