Whether the effect of Christ's priesthood is the expiation of sins?

❌ Objection 1 : It would seem that the effect of Christ's priesthood is not the expiation of sins. For it belongs to God alone to blot out sins, according to Is. 43:25: "I am He that blot out thy iniquities for My own sake." But Christ is priest, not as God, but as man. Therefore the priesthood of Christ does not expiate sins.

❌ Objection 2 : Further, the Apostle says (Heb. 10:1-3) that the victims of the Old Testament could not "make" (the comers thereunto) "perfect: for then they would have ceased to be offered; because the worshipers once cleansed should have no conscience of sin any longer; but in them there is made a commemoration of sins every year." But in like manner under the priesthood of Christ a commemoration of sins is made in the words: "Forgive us our trespasses" (Mt. 6:12). Moreover, the Sacrifice is offered continuously in the Church; wherefore again we say: "Give us this day our daily bread." Therefore sins are not expiated by the priesthood of Christ.

❌ Objection 3 : Further, in the sin-offerings of the Old Law, a he-goat was mostly offered for the sin of a prince, a she-goat for the sin of some private individual, a calf for the sin of a priest, as we gather from Lev. 4:3,23,28. But Christ is compared to none of these, but to the lamb, according to Jer. 11:19: "I was as a meek lamb, that is carried to be a victim." Therefore it seems that His priesthood does not expiate sins.