What is the Eucharist?

The Eucharist is the central sacrament of the Catholic Church — the one Catholics attend Mass every Sunday to receive, the one the Catechism calls "the source and summit of the Christian life," and the one that has most sharply divided Christian traditions for five hundred years. This post answers what the Eucharist actually is, in the plainest terms, with the Church's own words.

What does the Catholic Church mean by "the Eucharist"?

The Eucharist is one of the seven sacraments of the Catholic Church, and the sacrament the Church treats as the centre of its life. At Mass, the bread and wine offered by the priest are really changed into the body and blood of Jesus Christ. What the congregation receives in Communion is, according to the Church, Christ himself.

The word Eucharist comes from the Greek eucharistia, meaning "thanksgiving." It echoes Christ's own action at the Last Supper, when he took bread, gave thanks, broke it, and gave it to his disciples. Catholics use several names for this sacrament — the Mass, the Blessed Sacrament, Holy Communion, the Lord's Supper — but "Eucharist" emphasises both the gift and the response of thanks to it.

Where does the Eucharist come from?

It comes from Jesus himself. At the Last Supper, recorded in three of the four gospels and in St. Paul's letters, Jesus took bread and said: "This is my body, which is given for you. Do this in remembrance of me" (Luke 22:19). Matthew's account is equally direct: Jesus took bread, blessed it, broke it, and said, "Take, eat; this is my body" (Matthew 26:26).

The Church has understood these words in their plain sense from the beginning. St. Paul, writing within twenty years of the crucifixion, warned the Corinthian church that anyone who eats the bread "in an unworthy manner" is "guilty of profaning the body and blood of the Lord" (1 Corinthians 11:27). The warning only makes sense if Paul and his readers believed the bread really was the body of the Lord.

Belief in the Real Presence is not a medieval innovation. Ignatius of Antioch, writing around 110 AD, called the Eucharist "the flesh of our Saviour Jesus Christ." Justin Martyr, around 150 AD, wrote that Christians do not receive the consecrated elements "as common bread and common drink." The Fourth Lateran Council (1215) and the Council of Trent (1551) did not invent the doctrine; they defined it formally against emerging denials.

Is the Eucharist a symbol, or actually the body of Christ?

It is the body of Christ. The Catechism is unambiguous. In the Eucharist, "the body and blood, together with the soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained" (CCC 1374).

The three adverbs are load-bearing. Truly excludes the view that Christ is only figuratively present. Really excludes the view that he is present only in the faith of the believer. Substantially excludes the view that his presence is merely a spiritual influence on an unchanged piece of bread.

This does not mean the appearance changes. The consecrated host does not look, taste, or chemically analyse as anything other than bread; the wine remains wine to every physical test. What changes is what the Church calls the substance — the underlying reality of what the bread and wine are. After the consecration, the appearance is still bread and wine. The reality is Christ.

Jesus himself anticipated that this teaching would be hard to accept. In the sixth chapter of John's gospel, after promising the bread of life, he told his followers plainly: "Unless you eat the flesh of the Son of Man and drink his blood, you have no life in you" (John 6:53). Many disciples walked away. He did not call them back or soften the language.

The behaviour of Catholics around the consecrated elements follows from this. Catholics genuflect (bend the right knee) when passing the tabernacle. A consecrated host that is dropped is retrieved, not replaced. Fragments are collected. None of this makes sense if the Eucharist is a symbol. All of it makes sense if it is Christ.

What is transubstantiation?

Transubstantiation is the technical word the Catholic Church uses for what happens at the consecration. The Catechism quotes the Council of Trent directly:

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. CCC 1376

The term breaks down into trans- (across) and substantia (substance): a change across substances. It borrows vocabulary from Aristotelian philosophy, which distinguishes between the substance of a thing (what it fundamentally is) and its accidents (its outward properties: taste, colour, shape, weight). At the Eucharist, the substance changes. The accidents do not.

This is a mystery, not a magic trick. The Church does not claim to explain how the change happens — the philosophical terminology is meant to fence the truth against error, not to reduce it to a mechanism. The claim is simply that the change is real, because Christ said it was, and the Church has believed him from the beginning.

Why is the Eucharist called "the source and summit"?

The phrase is from the Second Vatican Council and has become one of the most quoted lines in modern Catholic teaching. The Catechism carries it forward: the Eucharist is "the source and summit of the Christian life" (CCC 1324).

Source means that everything in Christian life flows from it. The other sacraments — Baptism, Confirmation, Confession, Marriage, Holy Orders, Anointing of the Sick — are all oriented to it. The daily life of prayer and charity is fed by it. A Catholic who stops receiving the Eucharist tends, over time, to stop doing everything else.

Summit means that everything in Christian life points toward it. The highest act a Catholic can participate in on earth is the Mass, where Christ makes himself present and offers himself to the Father and to the faithful. Prayer, study, works of mercy, moral effort — these are not alternatives to the Eucharist. They prepare for it and culminate in it.

One practical consequence: Catholic parishes organise themselves around the Mass. The building is designed around the altar. The liturgical calendar is built around weekly Eucharists and a handful of high feasts. The parish staff, the choir, the catechism classes all exist primarily to support this one action. If the Eucharist is really Christ, this structure makes sense. If it is not, Catholic practice is strangely organised.

How does Catholic teaching differ from Protestant views?

Protestant positions vary widely. Lutheran traditions largely affirm a real presence of Christ in the bread and wine, though without the philosophical framework of transubstantiation. Reformed and most evangelical traditions treat communion as a memorial — a symbolic act of remembering Jesus, without any ontological change to the elements. Anglican practice spans both poles.

The Catholic position is distinct from both extremes. It affirms a substantial change, which memorialist views deny. And it offers a specific account of what that change is, which some "mysterious real presence" views leave open.

The difference is not stubbornness on the Catholic side. It is a commitment to the plain meaning of Christ's words at the Last Supper, the teaching of Paul to the Corinthians, the universal understanding of the Church in the first millennium, and the formal definitions of the Church in later councils. Ecumenical dialogue has made real progress on this question in recent decades, but genuine theological differences remain.

How should you prepare to receive the Eucharist?

Catholics are asked to prepare with care, because what they are receiving is Christ himself. "To respond to this invitation we must prepare ourselves for so great and so holy a moment" (CCC 1385).

Practical preparation has three components.

Examination of conscience. Before receiving, a Catholic considers whether serious sin has broken communion with God. If so, the Church asks the person first to receive the sacrament of confession. St. Paul is explicit: "Let a man examine himself, and so eat of the bread and drink of the cup" (1 Corinthians 11:28).

The Eucharistic fast. Catholics do not eat or drink anything, except water and medicine, for one hour before receiving Communion. It is a small, ancient discipline that creates a physical space of attention and anticipation.

Interior disposition. The most important preparation is not external but internal: approaching the altar with real faith that this is Christ, with gratitude for the gift, and with a genuine willingness to be changed by what one is receiving. A Catholic who receives the Eucharist distracted, reluctant, or only out of habit has received validly, but has not received fully.

These three together make the difference between attending Mass and participating in it.

The Eucharist is not a private devotion or a personal feeling. It is a public claim about what happens at a specific place at a specific moment, through the words of a specific man, using specific matter Christ himself chose. Catholics stake a great deal on that claim, because Christ staked a great deal on it first — and because the Church has staked everything on it from the first generation of Christians to the present Mass.