There are four purposes of the Mass, once memorised as an acronym,PART (Petition, Adoration, Reparation, Thanksgiving) and so
we redeemed Christian Catholics take time to prepare our own selves silently before Mass so that we, in a true, contrite, honest, and humble, spirit, Petition God for our needs, Adore our Triune God from whom all good things come, offer our Reparation for sins we have committed, and Thank Him for all of our blessings.
And after the Consecration, we Christian Catholics are invited to Communion, the Heavenly Banquet in which we Christian Catholics have the magnificent privilege of being able to participate in the New Covenant Meal.
So, in essence, The Holy Sacrifice of The Mass is that Once-For-All Sacrifice of Jesus on Calvary made present in our time (as actualised by The Holy Ghost) on our Altars as both a Holy Sacrifice (through the separate consecration of the bread and wine) of The New Covenant and the Banquet of The New Covenant. It is the action of Jesus which is the essence of The Mass. It is not what I do that is the essence of the Mass; nor is it the personality of the Priest that s the essence of the Mass; nor is the existence of The Mass a purpose for me to consider what I "get out of it." It is not for my entertainment or amusement. The purpose of The Mass is Salvation.
One purpose of the Incarnation was for the God-Man, Jesus, to teach us how to Worship our Triune God in spirit and in truth and it was on Maundy Thursday that Jesus taught His Apostles how to offer the Sacrifice of the New Covenant * and He made the Priests so that,through them, He could offer Himself, as both Priest and Victim, in the Sacrifice of the New Covenant.
St. Andrew, Apostle
Father Francis Xavier Weninger, 1876
The holy Apostle, St. Andrew, born at Bethsaida, in Galilee, was a brother of St. Peter, and at first a disciple of St. John the Baptist. He was the first of the Apostles who had the happiness of knowing Christ, the true Messiah; for, one day, when Andrew and another disciple were standing with their master on the banks of the Jordan, St. John, pointing to Jesus, who was approaching, said: "Behold the Lamb of God!" No sooner had Andrew heard these words, than he and the other disciple followed Christ, and remained with Him that day.
On the following day, meeting his brother, Simon, afterward called Peter, he said to him: "We have found the Messiah," and brought him to Christ. Not long after this, when Andrew and Peter were casting their nets into the Sea of Galilee, Christ called them, and said: "Come after Me, and I will make you to become fishers of men!" Immediately leaving their nets, they followed Him. From that moment, Andrew left the Lord no more, except at the time when He was seized in the Garden of Gethsemane, by the Jews, when he fled like the other disciples.
He was present when Christ, after His resurrection, appeared to His disciples; when He ascended into heaven in their presence, and when He sent the Holy Ghost from heaven upon them. When the Apostles separated, and went into the different countries of the world, to preach the Gospel of Christ to all nations, Andrew travelled into Scythia, Thrace, Galatia and other Pagan countries, where he converted many thousands by his sermons, and by the miracles he performed. At last he came to Patrae, the capital of Achaia, in Greece, and there, too, preached, with apostolic freedom, the Word of the Lord, and approved it by many miracles, which induced a great number of the inhabitants to embrace Christianity. Egeas, the governor, resisted him with all his might, and endeavored to defend idolatry. The holy Apostle, however, reproved him fearlessly, and said: "You desire that this people should recognize you as their judge; why, then, do you refuse to recognize Christ, the true God, as the Judge of all mankind; and why do you refuse to turn your heart from idolatry?"
"Be silent!" replied Egeas, "and speak not to me of your Christ. Was he not nailed by the Jews to a cross? How then can he be a true God? How can I worship him as God?" Andrew endeavored to explain the great mystery of the Redemption of the human race, and to show how Christ had, voluntarily, and for love of man, died the ignominious death of the cross; but, Egeas would not listen, and, interrupting him, commanded him immediately to sacrifice to the gods, or to prepare himself for a most cruel martyrdom. Andrew replied: * "I offer daily, on the Altar, to the Almighty, who is the only true God, not the flesh of oxen, nor the blood of goats, but an unspotted Lamb, which, when the entire multitude of the faithful have partaken of its flesh, remains entire and living." The governor, full of wrath, ordered Andrew to be cast into a dungeon; but the people, who loved the Saint as a father, rose against the governor, and ran in crowds to the dungeon, determined to set the prisoner free. But the Apostle besought them to be quiet, and not seek to prevent him from receiving the crown of martyrdom, which he had so long desired.