Hebrews 9:25-26
Nor was it to offer Himself repeatedly, as the high priest enters the Holy Place yearly with blood not his own; for then He would have had to suffer repeatedly since the foundation of the world. But as it is, He has appeared once for all at the end of the age to put away sin by the sacrifice of Himself.
Today's verse is one of the all-time favorites among critics of the Holy Sacrifice of the Mass. Such critics allege that the Mass "sacrifices Jesus again and again." In reality, however, the Mass is a participation in the one and only sacrifice there ever has been, will be, or even could be for the sins of the world: the sacrifice of Christ. Since it is a real participation, it is a real sacrifice, for Christ is our Paschal Sacrifice. But since it is a participation, it is not a repetition. The Christ Who is present on the altar under the appearance of bread and wine is the very same Christ Who died on the cross two thousand years ago. The sacrifice into which we enter is the one and only sacrifice He ever offered on Calvary. And the new life we receive from Him Who is really present in the Eucharist is the Risen Life He brought with Him out of the tomb.