Roman Catholic Christians share with most Christians the faith that Jesus Christ, on the night he was betrayed, ate a final or last supper with his Apostles. This final meal was also the celebration of the Jewish Passover or Feast of the Unleavened Bread which commemorated the passing over of the Jews from the death in slavery to the Egyptians to life in the Promised Land.
Christians differ in the meaning this Last Supper has to them and the Church today. Catholic Christians together with other historical Christian Churches (e.g., Eastern Orthodox and Byzantine Christians, Lutherans, Anglicans and some Episcopalians, etc.) believe the literal words of Jesus – that the bread and wine are truly his body and blood. Other later Christian Churches profess a mere symbolic meaning to the words of Jesus.
The faith of the Catholic Church is based on both a fundamental principle of hermeneutics and the constant faith of the Church from Apostolic times.
The next New Testament text in chronological order would have been Mark’s Gospel.
Written about 64 AD, in Rome, Mark, not an eyewitness, probably heard the account of the Last Supper he recorded from the Apostle Peter.
Mk 14:22-24
While they were eating, he took bread, said the blessing, broke it, and gave it to them, and said, “Take it; this is my body.” Then he took a cup, gave thanks, and gave it to them, and they all drank from it. He said to them, “This is my blood of the covenant, which will be shed for many.”
The third account of the Last Supper could be Matthew’s. Matthew, the tax collector Levi, was an eyewitness to the meal. He was one of the twelve Apostles. Matthew probably wrote his Gospel in the 70’s.
Mt 26:26-28
While they were eating, Jesus took bread, said the blessing, broke it, and giving it to his disciples said, “Take and eat; this is my body.” Then he took a cup, gave thanks, and gave it to them, saying, “Drink from it, all of you, for this is my blood of the covenant, which will be shed on behalf of many for the forgiveness of sins.”
Luke’s account of the Last Supper, written from the standpoint of a Gentile convert and a non-eyewitness, probably heard the details of the Last Supper from Paul. Luke was a traveling companion of Paul. Luke also wrote in the 70’s.
Lk 22:15-20
He (Jesus) said to them, “I have eagerly desired to eat this Passover with you before I suffer, for, I tell you, I shall not eat it (again) until there is fulfillment in the kingdom of God.” Then he took a cup, gave thanks, and said, “Take this and share it among yourselves; for I tell you (that) from this time on I shall not drink of the fruit of the vine until the kingdom of God comes.” Then he took the bread, said the blessing, broke it, and gave it to them, saying, “This is my body, which will be given for you; do this in memory of me.” And likewise the cup after they had eaten, saying, “This cup is the new covenant in my blood, which will be shed for you.”
The Mass: Synagogue Service and Last Supper
Roman Catholic Christians celebrate the Eucharist in the liturgical act called the Mass. The word Mass comes from the Latin missa (“sent”). It was taken from the formula for dismissing the congregation: Ite missa est (“Go, the Eucharist has been sent forth”) referring to the ancient custom of sending consecrated bread from the bishop’s Mass to the sick and to the other churches.
The Mass contains two parts: the liturgy of the Word and the Liturgy of the Eucharist. The Liturgy of the Word is a copy of the Jewish synagogue service of the first century: readings from Scripture followed by responses from the congregation often from the Book of Psalms. The Liturgy of the Eucharist is a reenactment of the Last Supper. A celebrant does what Christ did: take bread and wine and say the same words Christ said and then share the now consecrated bread and wine with the congregation.
Roman Catholics believe that the bread and wine become the real Body and Blood of Jesus Christ and remain such until the elements are entirely consumed. The Body and Blood not consumed at one Eucharist are reserved for the next celebration of the Eucharist and venerated as the Body and Blood of Jesus.
Source: catholicapologetics.org