The Eucharist embodies the central elements of our Christian faith. The most obvious element is the Lord who remains in our world sacramentally, not leaving us orphaned through his death but remaining with us in a tangible way. God’s choice to enter our world and become truly human in Jesus, meant that that Jesus must die and cease to be among us in ordinary human form. Through his gift to us of the Eucharist at the Last Supper, Jesus continues among us in a sacramental presence under the form of bread and wine. Secondly through Jesus’ life and sacrificial death we become brothers and sisters. As a true family of faith we gather around the altar. The practice of gathering as a community of faith sharing Scripture and breaking bread is as ancient as the Church.
Eucharist is simple but multi-faceted. The term “eucharist” derives from the Greek word for thanksgiving. We use the term both for the whole action of the Mass and for the sacramental presence of Christ received in Holy Communion because in sharing in Jesus self-sacrifice and his breaking of the bread, we are moved to give God thanks and praise for this great redeeming mystery. The Mass is directed to God as praise and worship it also nurtures us in our faith. We are fed with the Word of God and with his grace poured out in the Eucharist.
There is no question about the gathering for Eucharist in the early church. There is also no question that the Biblical Christians embraced an understanding of Christ’s presence in the Eucharist. St. Paul says in 1 Corinthians 11:23-29
For I received from the Lord what I also handed on to you, that the Lord Jesus, on the night he was handed over, took bread, and, after he had given thanks, broke it and said, “This is my body that is for you. Do this in remembrance of me.” In the same way also the cup, after supper, saying, “This cup is the new covenant in my blood. Do this, as often as you drink it, in remembrance of me.” For as often as you eat this bread and drink the cup, you proclaim the death of the Lord until he comes.
Therefore whoever eats the bread or drinks the cup of the Lord unworthily will have to answer for the body and blood of the Lord. A person should examine himself, and so eat the bread and drink the cup. For anyone who eats and drinks without discerning the body, eats and drinks judgment on himself.
Paul’s account in First Corinthians largely recounts the institution of the Eucharist by Jesus at the Last Supper. Justin Martyr in his Apologia or explanation to the emperor recounts the actual practice of the early church. You will easily recognize the current practice of the church.
Chapter 66. Of the Eucharist And this food is called among us Εὐχαριστία [the Eucharist], of which no one is allowed to partake but the man who believes that the things which we teach are true, and who has been washed with the washing that is for the remission of sins, and unto regeneration, and who is so living as Christ has enjoined. For not as common bread and common drink do we receive these; but in like manner as Jesus Christ our Savior, having been made flesh by the Word of God, had both flesh and blood for our salvation, so likewise have we been taught that the food which is blessed by the prayer of His word, and from which our blood and flesh by transmutation are nourished, is the flesh and blood of that Jesus who was made flesh. For the apostles, in the memoirs composed by them, which are called Gospels, have thus delivered unto us what was enjoined upon them; that Jesus took bread, and when He had given thanks, said, “This do in remembrance of Me, this is My body;” and that, after the same manner, having taken the cup and given thanks, He said, “This is My blood;” and gave it to them alone…
Chapter 67. Weekly worship of the Christians … And on the day called Sunday, all who live in cities or in the country gather together to one place, and the memoirs of the apostles or the writings of the prophets are read, as long as time permits; then, when the reader has ceased, the president verbally instructs, and exhorts to the imitation of these good things. Then we all rise together and pray, and, as we before said, when our prayer is ended, bread and wine and water are brought, and the president in like manner offers prayers and thanksgivings, according to his ability, and the people assent, saying Amen; and there is a distribution to each, and a participation of that over which thanks have been given, and to those who are absent a portion is sent by the deacons.
And they who are well to do, and willing, give what each thinks fit; and what is collected is deposited with the president, who succors the orphans and widows and those who, through sickness or any other cause, are in want, and those who are in bonds and the strangers sojourning among us, and in a word takes care of all who are in need. But Sunday is the day on which we all hold our common assembly, because it is the first day on which God, having wrought a change in the darkness and matter, made the world; and Jesus Christ our Savior on the same day rose from the dead. For He was crucified on the day before that of Saturn (Saturday); and on the day after that of Saturn, which is the day of the Sun, having appeared to His apostles and disciples, He taught them these things, which we have submitted to you also for your consideration.
The Catholic Catechism is a guide to the Church’s self-understanding as it has developed over the centuries under the guidance of the Holy Spirit, which we believe continues in the Church to this very day. From the Catholic Catechism found at http://www.usccb.org/catechism/text/
1406 Jesus said: “I am the living bread that came down from heaven; if any one eats of this bread, he will live for ever; . . . he who eats my flesh and drinks my blood has eternal life and . . . abides in me, and I in him” (Jn 6:51, 54, 56).
1407 The Eucharist is the heart and the summit of the Church’s life, for in it Christ associates his Church and all her members with his sacrifice of praise and thanksgiving offered once for all on the cross to his Father; by this sacrifice he pours out the graces of salvation on his Body which is the Church.
1408 The Eucharistic celebration always includes: the proclamation of the Word of God; thanksgiving to God the Father for all his benefits, above all the gift of his Son; the consecration of bread and wine; and participation in the liturgical banquet by receiving the Lord’s body and blood. These elements constitute one single act of worship.
1409 The Eucharist is the memorial of Christ’s Passover, that is, of the work of salvation accomplished by the life, death, and resurrection of Christ, a work made present by the liturgical action.
1410 It is Christ himself, the eternal high priest of the New Covenant who, acting through the ministry of the priests, offers the Eucharistic sacrifice. And it is the same Christ, really present under the species of bread and wine, who is the offering of the Eucharistic sacrifice.
1411 Only validly ordained priests can preside at the Eucharist and consecrate the bread and the wine so that they become the Body and Blood of the Lord.
1412 The essential signs of the Eucharistic sacrament are wheat bread and grape wine, on which the blessing of the Holy Spirit is invoked and the priest pronounces the words of consecration spoken by Jesus during the Last Supper: “This is my body which will be given up for you. . . . This is the cup of my blood. . . .”
1413 By the consecration the transubstantiation of the bread and wine into the Body and Blood of Christ is brought about. Under the consecrated species of bread and wine Christ himself, living and glorious, is present in a true, real, and substantial manner: his Body and his Blood, with his soul and his divinity (cf. Council of Trent: DS 1640; 1651).
414 As sacrifice, the Eucharist is also offered in reparation for the sins of the living and the dead and to obtain spiritual or temporal benefits from God.
1415 Anyone who desires to receive Christ in Eucharistic communion must be in the state of grace. Anyone aware of having sinned mortally must not receive communion without having received absolution in the sacrament of penance.
1416 Communion with the Body and Blood of Christ increases the communicant’s union with the Lord, forgives his venial sins, and preserves him from grave sins. Since receiving this sacrament strengthens the bonds of charity between the communicant and Christ, it also reinforces the unity of the Church as the Mystical Body of Christ.
1417 The Church warmly recommends that the faithful receive Holy Communion when they participate in the celebration of the Eucharist; she obliges them to do so at least once a year.
1418 Because Christ himself is present in the sacrament of the altar, he is to be honored with the worship of adoration. “To visit the Blessed Sacrament is . . . a proof of gratitude, an expression of love, and a duty of adoration toward Christ our Lord” (Paul VI, MF66).
1419 Having passed from this world to the Father, Christ gives us in the Eucharist the pledge of glory with him. Participation in the Holy Sacrifice identifies us with his Heart, sustains our strength along the pilgrimage of this life, makes us long for eternal life, and unites us even now to the Church in heaven, the Blessed Virgin Mary, and all the saints.