Antiquity recognized the Eucharist as Christ’s real presence.
Justin martyr (c. 100-165) in his Apologia explains for the benefit of Pagan readers:
This food is called among us the Eucharist, and of it, no one is allowed to partake unless he believes that our teaching is true and has been bathed in the waters for the forgiveness of sins and for regeneration, and is living as Christ commanded. For we do not receive it as common bread or common drink, but, just as Jesus Christ, our Savior made flesh by the Word of God, has both flesh and blood for our salvation, so also we have been taught that the food over which thanksgiving has been made, by the prayer of the Word that is from him, that food—from which our blood and flesh are by assimulation nourished—is both the flesh and the blood of the Jesus who was made flesh. (The Holy Eucharist, Nichols, 36)
Council of Trent defines transubstantiation
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.” (CCC1376)
Body, Blood, Soul, Divinity: whole, true, real, and substantial
[In the Most Blessed Sacrament of the Eucharist] the body and blood, together with the whole soul and divinity, of our Lord Jesus Christ and, therefore, the whole Christ is truly, really, and substantially contained. (The Council of Trent, DS 1651; Adoration, Guernsey, 80)
Transubstantiation changes bread and wine into His Body and Blood
The sacramental re-presentation of Christ’s sacrifice, crowned by the resurrection, in the Mass involves a most special presence which… “is called ‘real’ not as a way of excluding all other types of presence as if they were ‘not real’, but because it is a presence in the fullest sense: a substantial presence whereby Christ, the God-Man, is wholly and entirely present”. … Truly the Eucharist is a mysterium fidei, a mystery which surpasses our understanding and can only be received in faith… (Ecclesia de Eucharistia, Pope John Paul II, #15)
The underlying meaning of Transubstantiation
Transubstantiation… means the conversion of the Bread and Wine into the Body and Blood of Christ, in such a complete manner that none of the substance of the Bread or Wine remains, but only the species thereof. It implies that…
- Our Lord’s Body does not come by being moved thither locally, or by being created afresh, but by the Bread being changed into it.
- The substance of Bread (or of wine) ceases or comes to an end
- Our Lord’s Sacred Body comes, and is truly and really there
- The bread is “converted into” His Body
- The accidents, or qualities of the bread or wine (…the species, or appearances) continue and exist apart from, and without, the substance of the bread or wine
- The “conversion” here laid down is fittingly called by the name of Transubstantiation. (The Holy Eucharist, Hedley, 40)
Accidents exist in a thing but not on their own. They are how a thing is.
The accidents of a thing are the changeable conditions which do not directly belong to the essence of the thing, but rather answer the question of how a thing is. We know a thing first by its accidents because our senses can perceive only the sensible accidents of things and not the substance per se. Accidents include the sensible aspects of color, taste, smell, sound, heat, texture, size, position, movement and so on. They also extend to spiritual realities such as knowledge, virtue, and grace. An accident is something whose nature is to exist in a subject. Its nature is to have being not in itself, but in another. (Eucharist, Feingold, 260)
Substance is the underlying reality. It exists in itself (subsist).
Substance refers to the reality that underlies all the outward appearances or changeable accidents of the thing and gives it its identity. The term substance comes from the Latin to stand under because the substance is the reality that stands under the accidents. .. [It] is said to subsist, as existing not in another but in itself. (Eucharist, Feingold, 260)
Substance is what a thing is. It has being in itself. Accidents have being through the substance.
Substance answers the question of what a thing is. It is the substance that has being in itself; the accidents have being through the substance. The substance is the whole and abiding subject in which the accidents inhere. (Eucharist, Feingold, 260)
It is a two-fold miracle: conversion of substance and preservation of accidents.
Transubstantiation involves a two-fold miracle: a miraculous conversion of substance and a preservation of the accidents. There is the complete and instantaneous conversion of the substance of bread and wine into Christ. Secondly, however, God continues to maintain the existence of all the appearances or accidents of the bread and wine, even though the substance of bread and wine that formerly sustained them in being has been converted into Christ’s Body and Blood. (Eucharist, Feingold, 268)