[Following a brief discussion about how prayer and the Eucharist are the principal means for growing in holiness and in perfecting the life in Christ]:
The Eucharist is another means, but more powerful. When we pray, God communicates His gifts, under certain conditions. In the Sacrament of the Eucharist, it is God, it is Christ Himself who gives Himself to us; the Eucharist is specifically the sacrament of union which nourishes the divine life and keeps it within us. It is of the Eucharist that Our Lord was able to say very particularly: “I came that they may have life, and have it more abundantly.” (John 10:10). By receiving Christ in Holy Communion, we unite ourselves to Life itself.
But before giving Himself as food for the soul, Christ has first been immolated; it is only in the Sacrifice of the Mass that He renders Himself present under the sacramental species. That is why I must first speak to you of the oblation at the altar, postponing until my following address my talking to you about Eucharistic Communion.
Let us, then, say what the Sacrifice of the Mass is, and what power of transformation into Jesus it contains for our souls.
The subject is an ineffable one. Even the priest, who makes the Eucharistic Sacrifice the center and sun of his life, is powerless to put into words the marvels Christ Jesus’s love has amassed there. Everything that a man, a created being, is able to say of this mystery which has issued from the heart of one who is God remains so much short of its reality, that when someone has said everything he knows about it, it seems as if he had said nothing about it at all. There is no subject of which the priest loves more to speak, and of which he altogether dreads to speak, so holy and so high is this mystery.
Let us ask faith to enlighten us; the Eucharistic Sacrifice is, par excellence, a mystery of faith, Mysterium fidei. In order to understand anything about it, one must go to Christ, by repeating to Him the words of St. Peter when Jesus announced this mystery to the Jews, and even some of His disciples were scandalized and left Him: “To whom shall we go, O Divine Master? You are the only one who utters words that lead us to eternal life.” (see John 6:69). And above all let us, as St. John said, believe in love, “know and believe the love God has for us.” (1 John 4:16). Our Lord willed to institute this sacrament at the very time when He was about to give us the greatest testimony of His love for us, by His Passion, and He willed that it be perpetuated among us “in remembrance of” Him. It was like the last thought, the last testament of His sacred heart: “Do this…in remembrance of me.” (1 Cor. 11:24).
The Council of Trent, as you know, has defined that the Mass is “a true sacrifice,” which “recalls and renews the immolation of Christ on Calvary The Mass is offered as a true sacrifice, properly so called.” (Sess. XXII, can. 1). “In this Divine Sacrifice which is accomplished in the Mass there is contained and there is immolated in an unbloody manner the same Christ who, on the altar of the cross, offered Himself in a bloody manner. There is but one single Victim; and the same Christ who offered Himself on the cross now offers Himself through the ministry of the priests; the manner of offering Himself is the only difference.” (Sess. XXII, can. 2). Thus, the Sacrifice of the altar essentially renews that of Golgotha; the difference resides only in the mode of the oblation. If, then, we want to understand the greatness of the Sacrifice offered at the altar, we must consider for a moment what it is that constitutes the value of the immolation of the cross. That value derives from the dignity of the High Priest and of the Victim.
–From Christ, Life of the Soul, by Blessed Columba Marmion