The one sacrifice of Calvary made present again on ten thousand altars every morning — the source and summit of the whole Christian life.
The Liturgy
The Mass is the central act of Catholic worship, the ritual within which the Eucharist is celebrated. It unfolds in two great movements. The Liturgy of the Word gathers the assembly for readings from scripture — usually an Old Testament passage, a psalm, an epistle, and a Gospel — followed by a homily and the recitation of the Nicene Creed. The Liturgy of the Eucharist then proceeds to the offering of bread and wine, the great prayer of thanksgiving (the anaphora or Eucharistic Prayer) in which the priest, acting in persona Christi, repeats Christ's words over the elements, and finally the distribution of Communion. The shape is ancient, traceable in outline to the second century, and the word Eucharist itself simply means "thanksgiving."
Transubstantiation
At the heart of the Mass stands the doctrine of transubstantiation: the teaching, defined at the Fourth Lateran Council in 1215 and refined with the philosophical tools of Thomas Aquinas, that at the words of consecration the whole substance of the bread becomes the substance of Christ's Body and the whole substance of the wine becomes his Blood, while the accidents — the appearance, taste, and texture of bread and wine — remain unchanged. What the senses register does not alter; what the thing is does. This is not a symbol standing in for an absent Christ but a real conversion of one reality into another, held to be effected by the power of God through the priest.
The Reformed Contrast
Here the communions divide as sharply as anywhere. The memorialist view — associated with Zwingli and widespread across evangelical Protestantism — treats the bread and wine as symbols only, the Supper as an act of remembrance and nothing more. Calvin himself held a middle position, a spiritual or pneumatic real presence: Christ is not locally present in the elements, but by the power of the Holy Spirit the faithful are truly lifted up to feed on the ascended Christ in heaven. Lutheranism affirms a real presence "in, with, and under" the bread (often labeled consubstantiation, though Lutherans dislike the term). Catholicism goes furthest, insisting on a substantial change in the elements themselves. It is worth stating each view on its own terms: the Reformed objection is not irreverence but a conviction that Christ's risen body is in heaven and cannot be locally multiplied, and that the Catholic view risks confusing sign and thing signified. The Catholic reply is that Christ meant exactly what he said — "This is my body" — and that the Church has believed it from the beginning.
The Real Presence and the Sacrifice Re-Presented
Two claims give the Mass its weight for Catholics. The first is the Real Presence: Christ is truly, really, and substantially present — body, blood, soul, and divinity — under the Eucharistic species, so that the reserved sacrament is worthy of adoration and the reception of Communion is a genuine encounter with the living Lord. The second is that the Mass is a sacrifice. It does not repeat or add to Calvary; it re-presents the one, unrepeatable sacrifice of the cross, making it sacramentally present so that the faithful of every age may participate in it. The priest offers, but the true priest and victim is Christ himself. This is why the Eucharist is called the source and summit of the Christian life: everything the church does flows from it and returns to it. The Reformed traditions reject the sacrificial language emphatically, holding Christ's sacrifice to be finished and unrepeatable in every sense — another edge of the same fault line.
Related
- Catholicism — Collection index
- The Seven Sacraments — The Eucharist among the seven
- The Holy Trinity — The God worshipped in the Mass
- Calvinism — The Reformed and memorialist views
- Doctors of the Church — Aquinas and the theology of the sacrament
- Christianity — The wider tradition's disputes over Communion