The letter to the Hebrews is often said to disprove the sacrificial nature of the Mass. For example, Hebrews 7:26-27 says, "For it was fitting that we should have a high priest, holy, innocent, undefiled, separated from sinners and exalted above the heavens; who does not need daily, like those high priests, to offer up sacrifices, first for his own sins, and then for the sins of the people, because this he did once for all when he offered up himself."
Notice Jesus offered his sacrifice "once for all." It's this "once for all".aspect of Christ's sacrifice, mentioned repeatedly in Hebrews, which supposedly refutes the sacrifice of the Mass.
"After all," ask opponents of the Mass, "if Christ has offered the perfect sacrifice for sins before God, why do we need another sacrifice in the Mass to receive the forgiveness of sins?"
If Catholics believed the Mass were a sacrifice in the sense implied by this question, there would be something to the objection. But this isn't how the Catholic Church sees the sacrifice of the Mass.
The Mass has always been held to be a relative sacrifice--relative to the sacrifice of the Cross, not independent of it. The Council of Trent says the Mass is the means "whereby that bloody sacrifice once to be accomplished on the Cross might be represented, the memory thereof remain even to the end of the world, and its salutary effects applied to the remission of those sins which we daily commit" (Session 22, chapter 1).
Trent continues by saying, "And inasmuch as in this divine sacrifice which is celebrated in the Mass is contained and immolated in an unbloody manner the same Christ who once offered himself in a bloody manner on the altar of the cross, the holy council teaches that this is truly propitiatory....For the victim is one and the same, the same now offering by the ministry of priests who then offered himself on the Cross, the manner alone of offering being different" (Session 22, chapter 2).
Frank Sheed summarizes Catholic teaching on the point in Theology and Sanity:
"There is no new slaying of Christ in the Mass....Yet that it is the Christ who was slain upon Calvary is shown sacramentally by the separate consecration of bread to become His body and wine to become His blood. The essence of the Mass is that Christ is making an offering to the Father of Himself, who was slain for us upon Calvary. The Mass is Calvary, as Christ now offers it to His Father."
Hebrews teaches the atoning death of Christ was effective for the remission of sins and hence needed to be offer only once. But this speaks of what theologians call the "objective redemption." It doesn't mean that, since Jesus died for everyone, everyone will get to heaven. (That's universalism.) The merits or the fruits of Christ's death need to be applied to the individual.
When Catholic theologians talk about the Mass being a propitiatory sacrifice for the remission of sins, they mean, among other things, that the objective redemption which Christ's sacrifice on the Cross merited is subjectively applied to the individual through the sacrifice of the Mass.
Christ's sacrifice objectively merited redemption on the Cross. The same sacrifice of Christ, now offered sacramentally, not physically, is applied to the individual in the Eucharist.
Far from substituting for the Cross or to make up for something that's lacking in Christ's sacrifice, the Mass is a means by which we receive the benefits of the Atonement.
Granted this is what the Catholic Church teaches about the Mass, and granted it doesn't mean Jesus is killed again by the priest, people still ask, "Doesn't Hebrews 7-11 contradict even a sacramental sacrifice when it says Christ offered one sacrifice?"
No. Remember, the sacrifice of the Mass is the sacrifice of the Cross, only presented in a different manner. The.aspect of redemption which involved his death is finished, but Christ lives forever to offer, by his very presence in the Mass, his work on the Cross for our sins to the Father in heaven. In no way does this diminish Calvary.
Read Hebrews 9:11-12: "When Christ came as high priest of the good things that have come to be, passing through the greater and more perfect tabernacle not made by hands...he entered once for all into the sanctuary, not with the blood of goats and calves but with his own blood, thus obtaining eternal redemption."
What does this means? In the Old Testament, atonement for the sins of the people was obtained once a year on the Day of Atonement when the high priest entered the holy of holies to offer sacrifices. Hebrews contrasts this with Christ who, as victim and high priest, offered the perfect sacrifice, once for all, on the Cross and who presented himself, as both victim and priest, in the true tabernacle, which is heaven itself, the dwelling place of God (Heb. 8:2-3; 9:11-12, 24).
Christ IS "always able to save those who approach God through him, since he lives forever to make intercession for them" (Heb. 7:25). What is the basis of this intercession? The sacrifice of the Cross (Heb. 7:27; 9:12; 10:14), which is forever present before God in the heavenly tabernacle because he who was both offered as victim and who offered the sacrifice as priest "appears before God on our behalf" (Heb. 9:24).
Christ's perfect offering of himself present in heaven (Heb. 9:11-12) is brought to earth in an unbloody, sacramental manner in the Mass. As Frank Sheed puts it, "The Mass is the breaking through to earth of the offering of Himself that Christ makes continuously in heaven simply by His presence there."
Some people will still object that the Mass is actually the reverse of the Cross. On the Cross Christ offered himself for us: We didn't offer anything. In the Mass, on the other hand, we do the offering.
In a sense, this is true. We weren't physically or personally at Calvary. Still, there's a sense in which we were present--present in our high priest, Jesus, who offered the sacrifice of himself for us.
In the Old Testament the high priest, in offering sacrifice for Israel, represented the people before God. In other words, the people offered their sacrifice through the high priest. Christ was our high priest, as well as our sacrifice, on Calvary. We offered the perfect sacrifice (Christ) for sins to the Father through him.
Similarly, in the Mass Christ offers himself to the Father on our behalf, and we, his people, join ourselves sacramentally to his offering. The Mass is a way of approaching God through Christ's sacrifice, which is made present sacramentally because Christ himself is present.
Nothing in this diminishes Calvary or implies we can approach God other than through the Cross. Rather than taking away from the Cross, the Mass emphasizes it.