The Paschal Mystery, which kicked off this great season of Easter, not only finished with the resurrection of our Blessed Lord, but also culminated in the consummation of the new covenant. A covenant that Saint Stephen, and countless other martyrs throughout the age of the Church, have willingly sacrificed their lives in their personal response to what God initiated.
Throughout history, the establishment of a covenant required two things: an initiation by one party and a response by the other party. God initiated a covenant with Adam, and Adam responded imperfectly. God initiated a covenant with Noah, and Noah responded imperfectly. God then initiated a covenant with Abraham, and Abraham also responded imperfectly. God initiated a covenant with Moses, and Moses (as you can probably guess) responded imperfectly. And, so one and so forth throughout the history of Israel in the Old Testament....until we get to the Last Supper.
At the Last Supper, in the context of the Jewish Passover, Jesus Christ through His divine nature initiated the new and everlasting covenant. Then, on the cross, Jesus Christ through His human nature offered the perfect response. On the cross, Jesus Christ drank from the fourth and final Passover cup (which is known as the Chalice of Hallel). On the cross, Jesus Christ sacrificed Himself as the true Lamb of God Who takes away the sins of the world. On the cross, Jesus declared the consummation of the new covenant finished.
This transaction between initiation of and response to the new and everlasting covenant is the authentic context of Jesus's role as our one and true mediator with God. Only Jesus Christ in His divinity could initiate an eternal covenant. Only Jesus Christ in His humanity could offer a perfect response.
At the Last Supper, Jesus instituted the Eucharist, the Bread of Life, to be our Passover Feast. The Eucharist is the way Jesus desires us to worship Him. But more than that: The Eucharist is the mechanism Jesus gave us that allows us to substantially participate in His one-and-for-all sacrifice on Calvary. The Eucharist is the mechanism Jesus gave us that allows us to efficaciously (effectively) participate in His perfect response to the new covenant.
This is why the Mass is so important. Without our active participation in the Mass, our personal response to the new covenant is imperfect at best, and quite possibly not efficacious. We need the Mass. We need the Eucharist. We need to drink from the chalice from which Jesus drank (namely, the Chalice of Hallel that is offered at every single Mass). We need to eat the Flesh of the Son of Man and drink His Blood in order to have salvation and eternal life. We need the Bread of Life!
