Para 1365: “Because it is the memorial of Christ's Passover, the Eucharist is also a sacrifice. The sacrificial character of the Eucharist is manifested in the very words of institution: ‘This is my body which is given for you’ and ‘This cup which is poured out for you is the New Covenant in my blood.’ In the Eucharist Christ gives us the very body which he gave up for us on the cross, the very blood which he ‘poured out for many for the forgiveness of sins.’”
Para 1368: The Eucharist is also the sacrifice of the Church. The Church which is the Body of Christ participates in the offering of her Head. With him, she herself is offered whole and entire. She unites herself to his intercession with the Father for all men. In the Eucharist the sacrifice of Christ becomes also the sacrifice of the members of his Body. The lives of the faithful, their praise, sufferings, prayer, and work, are united with those of Christ and with his total offering, and so acquire a new value. Christ's sacrifice present on the altar makes it possible for all generations of Christians to be united with his offering.
Para 1376: “The Council of Trent summarizes the Catholic faith by declaring: ‘Because Christ our Redeemer said that it was truly his body that he was offering under the species of bread, it has always been the conviction of the Church of God, and this holy Council now declares again, that by the consecration of the bread and wine there takes place a change of the whole substance of the bread into the substance of the body of Christ our Lord and of the whole substance of the wine into the substance of his blood. This change the holy Catholic Church has fittingly and properly called transubstantiation.’"
Para 1377: “The Eucharistic presence of Christ begins at the moment of the consecration and endures as long as the Eucharistic species subsist. Christ is present whole and entire in each of the species and whole and entire in each of their parts, in such a way that the breaking of the bread does not divide Christ.”
Para 1378: “Worship of the Eucharist. In the liturgy of the Mass we express our faith in the real presence of Christ under the species of bread and wine by, among other ways, genuflecting or bowing deeply as a sign of adoration of the Lord. ‘The Catholic Church has always offered and still offers to the sacrament of the Eucharist the cult of adoration, not only during Mass, but also outside of it, reserving the consecrated hosts with the utmost care, exposing them to the solemn veneration of the faithful, and carrying them in procession.’"
Para 2181: “The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor. Those who deliberately fail in this obligation commit a grave sin.”
In addition to teaching that the bread and wine actually become the body and blood of Christ, Rome teaches that the Eucharist is to be worshiped as Christ. The Code of Canon Law states that the faithful are to “hold the Eucharist in highest honor…worshiping it with supreme adoration.” According to Vatican II, this is to be with “the same worship of latria or adoration that we offer to God.” (both citations from James G. McCarthy, The Gospel According to Rome, P.131). Yet worshiping objects such as wine and bread is nothing less than idolatry, which Scripture specifically prohibits.
Let’s use a little common sense and reasoning here. If the Last Supper was in actuality a Mass, then how could Jesus be sitting there with the elements at the same time saying the elements were his body and blood? Do you think the disciples understood Jesus to be speaking literally, since the Law prohibited the eating of blood? And if the human body of Christ is located in heaven at the Father’s right hand, how can it be at the same time in millions of places in Masses all over the world? Isn’t it more likely that Jesus was using the bread and wine figuratively so as to provide Christians with symbols to celebrate with as a memorial?
Rome also claims that in the Eucharist Christ is sacrificed to God, and that the Last Supper was in itself a Mass. If the Last Supper was indeed a sacrifice of Christ, then we have an illogical situation of Christ sacrificing himself before he was sacrificed on the cross. Additionally, if each Mass is a sacrifice of Christ, then we have a direct contradiction of the Bible which says that Christ was sacrificed once for all time, and that this eliminated the need for continual sacrifices.
Hebrews 7:26-27: For such a High Priest was fitting for us, who is holy, harmless, undefiled, separate from sinners, and has become higher than the heavens; who does not need daily, as those high priests, to offer up sacrifices, first for His own sins and then for the people’s, for this He did once for all when He offered up Himself.
Hebrews 9:24-28: For Christ has not entered the holy places made with hands, which are copies of the true, but into heaven itself, now to appear in the presence of God for us; not that He should offer Himself often, as the high priest enters the Most Holy Place every year with blood of another— He then would have had to suffer often since the foundation of the world; but now, once at the end of the ages, He has appeared to put away sin by the sacrifice of Himself. And as it is appointed for men to die once, but after this the judgment, so Christ was offered once to bear the sins of many.
Hebrews 10:14: For by one offering He has perfected forever those who are being sanctified.
1 Peter 3:18a: For Christ also suffered once for sins, the just for the unjust, that He might bring us to God
Lastly, notice also that deliberately failing to participate in the Sunday Eucharist is a mortal sin, which would mean the person was in a state outside of grace and in danger of going to Hell. This would also mean that the Mass is necessary for salvation, thereby adding to the plain teaching of Scripture that we are saved by faith apart from works. (Acts 16:30-31).
The Roman church has many reasons why they claim this is all true, and twist the Scriptures to justify much of it. However, once the reasons are examined in light of Scripture in context, one is able see that the whole basis of this teaching is because the Church says so - because they are the Magisterium, and they have the authority to speak for God, while the Pope is Christ’s representative on earth. Of course, by examining the history of the papacy and of the Catholic Church, one sees immediately the fraudulent nature of these claims.