This bread our Lord then gave, when He delivered to His disciple the mystery of His Body and Blood, and offered Himself to God the Father on the altar of the cross. Forthe life of the world, i.e. not for the elements, but for mankind, who are called the world.

St. Bede the Venerable on John 6:51 He had said above, Whoso eats My flesh and drinks My blood, has eternal life: and now to show the great difference between bodily meat and drink, and the spiritual mystery of His body and blood, Ho adds, For My flesh its meat indeed, and My blood its drink indeed. And to show the wide interval between the shadow and the light, the type and the reality, He adds, Not as your fathers did eat manna, and are dead: he that eats of this bread shall live for ever.

St. Bede the Venerable on John 6:51 St. John of Damascus, c. 675 or 676 – 4 December 749 AD Receive the communion of the spotless mysteries of Christ, believing in fact that they are the body and blood of Christ our God, which he gave to the faithful for the forgiveness of sins. On the same night when he was betrayed, he ordained a new covenant with his holy disciples and apostles and through them for all that should believe on him. He said, “ ‘Take, eat, this is my body, which is broken for you, for the forgiveness of sins.’ In the same way he also took the cup and gave it to them saying, ‘Drink all of this. This is my blood of the new covenant, which is shed for you for the forgiveness of sins. Do this in memory of me.’ ”

He, the Word of God, is quick, powerful and working all things by his might. He makes and transforms the bread and wine of the sacrifice through his divine operation into his own body and blood, by the visitation of the Holy Spirit, for the sanctification and enlightenment of those who eagerly participate in it.

St. John of Damascus on Luke 22:19 Second Council of Nicaea, 787 AD The only admissible figure of the humanity of Christ, however, is bread and wine in the holy Supper. This and no other form, this and no other type, has he chosen to represent his incarnation. Bread he ordered to be brought, but not a representation of the human form, so that idolatry might not arise. And as the body of Christ is made divine, so also this figure of the body of Christ, the bread, is made divine by the descent of the Holy Spirit; it becomes the divine body of Christ by the mediation of the priest who, separating the oblation from that which is common, sanctifies it.

Second Council of Nicæa, Session 6 Belief In Real Presence Is Required For Catholics The Catholic Church has Dogmatically declared and defined belief in the Real Presence for one to remain a Catholic in good-standing.

Fourth Lateran Council, 1215 AD Canon 1:

There is one Universal Church of the faithful, outside of which there is absolutely no salvation. In which there is the same priest and sacrifice, Jesus Christ, whose body and blood are truly contained in the sacrament of the altar under the forms of bread and wine; the bread being changed (transsubstantiatio) by divine power into the body, and the wine into the blood, so that to realize the mystery of unity we may receive of Him what He has received of us. And this sacrament no one can effect except the priest who has been duly ordained in accordance with the keys of the Church, which Jesus Christ Himself gave to the Apostles and their successors.

Medieval Sourcebook: Twelfth Ecumenical Council: Lateran IV 1215 St. Thomas Aquinas, Summa Theologica, 13th Century I answer that, The presence of Christ’s true body and blood in this sacrament cannot be detected by sense, nor understanding, but by faith alone, which rests upon Divine authority. Hence, on Luke 22:19: “This is My body which shall be delivered up for you,” Cyril says: “Doubt not whether this be true; but take rather the Saviour’s words with faith; for since He is the Truth, He lieth not.”

Now this is suitable, first for the perfection of the New Law. For, the sacrifices of the Old Law contained only in figure that true sacrifice of Christ’s Passion, according to Hebrews 10:1: “For the law having a shadow of the good things to come, not the very image of the things.” And therefore it was necessary that the sacrifice of the New Law instituted by Christ should have something more, namely, that it should contain Christ Himself crucified, not merely in signification or figure, but also in very truth. And therefore this sacrament which contains Christ Himself, as Dionysius says (Eccl. Hier. iii), is perfective of all the other sacraments, in which Christ’s virtue is participated.

Secondly, this belongs to Christ’s love, out of which for our salvation He assumed a true body of our nature. And because it is the special feature of friendship to live together with friends, as the Philosopher says (Ethic. ix), He promises us His bodily presence as a reward, saying (Matthew 24:28): “Where the body is, there shall the eagles be gathered together.” Yet meanwhile in our pilgrimage He does not deprive us of His bodily presence; but unites us with Himself in this sacrament through the truth of His body and blood. Hence (John 6:57) he says: “He that eateth My flesh, and drinketh My blood, abideth in Me, and I in him.” Hence this sacrament is the sign of supreme charity, and the uplifter of our hope, from such familiar union of Christ with us.

Thirdly, it belongs to the perfection of faith, which concerns His humanity just as it does His Godhead, according to John 14:1: “You believe in God, believe also in Me.” And since faith is of things unseen, as Christ shows us His Godhead invisibly, so also in this sacrament He shows us His flesh in an invisible manner.

Some men accordingly, not paying heed to these things, have contended that Christ’s body and blood are not in this sacrament except as in a sign, a thing to be rejected as heretical, since it is contrary to Christ’s words. Hence Berengarius, who had been the first deviser of this heresy, was afterwards forced to withdraw his error, and to acknowledge the truth of the faith.

ST III, q. 75, a. 1 Council of Trent, 1551 AD THE REAL PRESENCE OF OUR LORD JESUS CHRIST IN THE MOST HOLY SACRAMENT OF THE EUCHARIST

First of all, the holy council teaches and openly and plainly professes that after the consecration of bread and wine, our Lord Jesus Christ, true God and true man, is truly, really and substantially contained in the august sacrament of the Holy Eucharist under the appearance of those sensible things.

For there is no repugnance in this that our Savior sits always at the right hand of the Father in heaven[3] according to the natural mode of existing, and yet is in many other places sacramentally present to us in His own substance by a manner of existence which, though we can scarcely express in words, yet with our understanding illumined by faith, we can conceive and ought most firmly to believe is possible to God.[4]

For thus all our forefathers, as many as were in the true Church of Christ and who treated of this most holy sacrament, have most openly professed that our Redeemer instituted this wonderful sacrament at the last supper, when, after blessing the bread and wine, He testified in clear and definite words that He gives them His own body and His own blood.

Since these words, recorded by the holy Evangelists[5] and afterwards repeated by St. Paul,[6] embody that proper and clearest meaning in which they were understood by the Fathers, it is a most contemptible action on the part of some contentious and wicked men to twist them into fictitious and imaginary tropes by which the truth of the flesh and blood of Christ is denied, contrary to the universal sense of the Church, which, as the pillar and ground of truth,[7] recognizing with a mind ever grateful and unforgetting this most excellent favor of Christ, has detested as satanical these untruths devised by impious men.

…

Canons on the Most Holy Sacrament of the Eucharist

Canon 1.If anyone denies that in the sacrament of the most Holy Eucharist are contained truly, really and substantially the body and blood together with the soul and divinity of our Lord Jesus Christ, and consequently the whole Christ,[42] but says that He is in it only as in a sign, or figure or force, let him be anathema.

Canon 2.If anyone says that in the sacred and, holy sacrament of the Eucharist the substance of the bread and wine remains conjointly with the body and blood of our Lord Jesus Christ, and denies that wonderful and singular change of the whole substance of the bread into the body and the whole substance of the wine into the blood, the appearances only of bread and wine remaining, which change the Catholic Church most aptly calls transubstantiation,[43] let him be anathema.

Canon 3.If anyone denies that in the venerable sacrament of the Eucharist the whole Christ is contained under each form and under every part of each form when separated,[44] let him be anathema.

Canon 4.If anyone says that after the consecration is completed, the body and blood of our Lord Jesus Christ are not in the admirable sacrament of the Eucharist,[45] but are there only <in usu>, while being taken and not before or after, and that in the hosts or consecrated particles which are reserved or which remain after communion, the true body of the Lord does not remain, let him be anathema.

Canon 5.If anyone says that the principal fruit of the most Holy Eucharist is the remission of sins, or that other effects do not result from it,[46] let him be anathema.

Canon 6.If anyone says that in the holy sacrament of the Eucharist, Christ, the only begotten Son of God, is not to be adored with the worship of <latria>,[47] also outwardly manifested, and is consequently neither to be venerated with a special festive solemnity, nor to be solemnly borne about in procession according to the laudable and universal rite and custom of holy Church, or is not to be set publicly before the people to be adored and that the adorers thereof are idolaters, let him be anathema.

Canon 7.If anyone says that it is not lawful that the Holy Eucharist be reserved in a sacred place, but immediately after consecration must necessarily be distributed among those present,[48] or that it is not lawful that it be carried with honor to the sick, let him be anathema.

Canon 8.If anyone says that Christ received in the Eucharist is received spiritually only and not also sacramentally and really,[49] let him be anathema.

Canon 9.If anyone denies that each and all of Christ’s faithful of both sexes are bound, when they have reached the years of discretion, to communicate every year at least at Easter,[50] in accordance with the precept of holy mother Church, let him be anathema.

Canon 10.If anyone says that it is not lawful for the priest celebrating to communicate himself,[51] let him be anathema.

Canon 11. If anyone says that faith alone is a sufficient preparation for receiving the sacrament of the most Holy Eucharist,[52] let him be anathema. And lest so great a sacrament be received unworthily and hence unto death and condemnation, this holy council ordains and declares that sacramental confession, when a confessor can be had, must necessarily be made beforehand by those whose conscience is burdened with mortal sin, however contrite they may consider themselves. Moreover, if anyone shall presume to teach, preach or obstinately assert, or in public disputation defend the contrary, he shall be <eo ipso> excommunicated.

Thirteenth Session of the Council of Trent The Douay Catechism of 1649 AD Q. What is the blessed Eucharist?

A. It is the body and blood of Jesus Christ, true God, and true man, under the outward forms of bread and wine.

Q. In what manner is Christ present under these forms?

A. By the true and real presence of his divine and human nature.

Q. How prove you that?

A. First out of Matt. xxvi. 27, 28. Christ at his last supper, took bread and blessed it, brake it and gave it to his disciples, saying, “Take eat, this is my body. And he blessed the cup saying, This is my blood of the New Testament which shall be shed for many to the remission of sins,” Mark xiv. 22, 24.

Secondly, out of Luke xxii. 19, 20. “This is my body which is given for you, this is the chalice of the New Testament in my blood, which shall be shed for you.”

Thirdly, out of John vi. 52, 53, 54. “The bread which I give is my flesh, for the life of the world; by flesh is meat indeed, and my blood is drink indeed; unless you eat the flesh of the Son of man, and drink his blood, you shall have no life in you.”

Fourthly, out of 1 Cor. xi. 23, where St. Paul tells us, “He received from our Lord,” (viz. by special revelation) that at his last supper he blessed bread, saying, “Take ye and eat, this is my body which shall be delivered up for you; this chalice is the New Testament in my blood.”

Q. By what means is the body and blood of Christ made under the outward forms of bread and wine?

A. By the real conversion or change of the whole substance of the body and blood of Christ; which conversion is wrought by the most holy and powerful words of consecration, instituted by Christ, and spoken by the priest, and is fitly called Transubstantiation, by the councils of Lateran and Trent; which signifies a passage or conversion of one substance into another.

Q. Is there any scripture for Transubstantiation?

A. The word Transubstantiation is not found in scripture, but for the thing signified by it, there are those places in scripture, which prove a real presence, because those words, This is my Body, spoken by Christ, after he had taken bread into his hands, and signifying that to be his body, which before was bread, cannot be true, without the change of of bread into his body; which change is (as I have said already) the thing signified or meant by Transubstantiation. Nor may the word be lawfully rejected for not being found in scripture more than other words used by the church, to explain mysteries of faith; as the word, Trinity or Consubstantiality of God the Son with God the Father, which are not found in scripture.

The Douay Catechism of 1649 by Henry Tuberville, D.D. The Baltimore Catechism, 1885 AD Q. 869. What does the word Eucharist strictly mean?

A. The word Eucharist strictly means pleasing, and this Sacrament is so called because it renders us most pleasing to God by the grace it imparts, and it gives us the best means of thanking Him for all His blessings.

Q. 870. What is the Holy Eucharist?

A. The Holy Eucharist is the Sacrament which contains the body and blood, soul and divinity, of our Lord Jesus Christ under the appearances of bread and wine.

Q. 871. What do we mean when we say the Sacrament which contains the Body and Blood?

A. When we say the Sacrament which contains the Body and Blood, we mean the Sacrament which is the Body and Blood, for after the Consecration there is no other substance present in the Eucharist.