Mysterium Fidei EN


9 However, venerable brothers, in this very matter which we are discussing, there are not lacking reasons for serious pastoral concern and anxiety. The awareness of our apostolic duty does not allow us to be silent in the face of these problems. Indeed, we are aware of the fact that, among those who deal with this Most Holy Mystery in written or spoken word, there are some who, with reference either to Masses which are celebrated in private, or to the dogma of transubstantiation, or to devotion to the Eucharist, spread abroad opinions which disturb the faithful and fill their minds with no little confusion about matters of faith. It is as if everyone were permitted to consign to oblivion doctrine already defined by the Church, or else to interpret it in such a way as to weaken the genuine meaning of the words or the recognized force of the concepts involved.

To confirm what we have said by examples, it is not allowable to emphasize what is called the "communal" Mass to the disparagement of Masses celebrated in private, or to exaggerate the element of sacramental sign as if the symbolism, which all certainly admit in the Eucharist, expresses fully and exhausts completely the mode of Christ's presence in this sacrament. Nor is it allowable to discuss the mystery of transubstantiation without mentioning what the Council of Trent stated about the marvelous conversion of the whole substance of the bread into the Body and of the whole substance of the wine into the Blood of Christ, speaking rather only of what is called
«transignification" and transfiguration," or finally to propose and act upon the opinion according to which, in the Consecrated Hosts which remain after the celebration of the sacrifice of the Mass, Christ Our Lord is no longer present.

Everyone can see that the spread of these and similar opinions does great harm to the faith and devotion to the Divine Eucharist.

And therefore, so that the hope aroused by the council, that a flourishing of eucharistic piety which is now pervading the whole Church, be not frustrated by this spread of false opinions, we have with apostolic authority decided to address you, venerable brothers, and to express our mind on this subject.

We certainly do not wish to deny in those who are spreading these singular opinions the praiseworthy effort to investigate this lofty mystery and to set forth its inexhaustible riches, revealing its meaning to the men of today; rather we acknowledge and approve their effort. However, we cannot approve the opinions which they express, and we have the duty to warn you about the grave danger which these opinions involve for correct faith.


15 First of all we wish to recall something which is well known to you but which is altogether necessary for repelling every virus of rationalism, something to which many illustrious martyrs have witnessed with their blood, while celebrating Fathers and Doctors of the Church constantly professed and taught it; that is, that the Eucharist is a very great mystery. In fact, properly speaking, and to use the words of the sacred liturgy, it is the Mystery of Faith.
«Indeed, in it alone," as Leo XIII our predecessor of happy memory very wisely remarked, "are contained, in a remarkable richness and variety of miracles, all supernatural realities." (4)

Encyclical Mirae Caritatis, Acta Leonis XIII, Vol. XXII, 1902-1903, p. 122.

16 We must therefore approach especially this mystery with humble respect, not following human arguments, which ought to be silent, but adhering firmly to divine revelation.

17 St. John Chrysostom, who, as you know, treated of the eucharistic mystery with such nobility of language and insight born of devotion, instructing his faithful on one occasion about this mystery, expressed these most fitting words:

"Let us submit to God in all things and not contradict Him, even if what He says seems contrary to our reason and intellect; rather let His words prevail over our reason and intellect. Let us act in this way with regard to the (eucharistic) mysteries, looking not only at what falls under our senses but holding on to His words. For His word cannot lead us astray." (5)

In Matth. Homil. 82, 4, Migne P.G. 58, 743.

18 The scholastic Doctors often made similar affirmations: That in this sacrament are the true Body of Christ and His true Blood is something that "cannot be apprehended by the senses," says St. Thomas, "but only by faith which relies on divine authority. This is why, in a comment on Lc 22,19 ('This is My Body which is given for you'), St. Cyril says: 'Do not doubt whether this is true, but rather receive the words of the Savior in faith, for since He is the truth, He cannot lie.'" (6)

Summ. Theol. III 77,10C

19 Thus the Christian people, echoing the words of the same St. Thomas, frequently sing the words: "Sight, touch, and taste in Thee are each deceived, the ear alone most safely is believed. I believe all the Son of God has spoken--than truth's own word there is no truer token."

20 In fact, St. Bonaventure asserts: "There is no difficulty about Christ's presence in the Eucharist as in a sign, but that He is truly present in the Eucharist as He is in heaven, this is most difficult. Therefore to believe this is especially meritorious." (7)

In. IV Sent. Dist. X. P. I Art. Un. Qu. I, Oper. Omn. Tom. IV Ad Claras Acquas 1889, p. 217.

21 Moreover, the Holy Gospel alludes to this when it tells of the many disciples of Christ who, after listening to the sermon about eating His Flesh and drinking His Blood, turned away and left our Lord, saying: "This is strange talk, who can be expected to listen to it?" Peter, on the other hand, in reply to Jesus' question whether also the twelve wished to leave, expressed his faith and that of the others promptly and resolutely with the marvelous answer: «Lord, to whom should we go? Thy words are the words of eternal life." (Jn 6,61-69)

22 It is logical, then, that we should follow as a guiding star in our investigations of this mystery the magisterium of the Church, to which the Divine Redeemer entrusted for protection and for explanation the revelation which He has communicated to us through Scripture or tradition. For we are convinced that "what since the days of antiquity was preached and believed throughout the whole Church with true Catholic Faith is true, even if it is not submitted to rational investigation, even if it is not explained by means of words." (9)

St. Augustine, Contr. Julian VI. 5, 11, Migne. P.L. 44, 829.

23 But this is not enough. Having safeguarded the integrity of the faith, it is necessary to safeguard also its proper mode of expression, lest by the careless use of words, we occasion (God forbid) the rise of false opinions regarding faith in the most sublime of mysteries. St. Augustine gives a stern warning about this in his consideration of the way of speaking employed by the philosophers of that which ought to be used by Christians.

"The philosophers," he says, "speak freely without fear of offending religious listeners on subjects quite difficult to understand. We, on the other hand, must speak according to a fixed norm, lest the lack of restraint in our speech result in some impious opinion even about the things signified by the words themselves." (10)

De Civit. Dei X, 23 P.L. 41,300.

24 The Church, therefore, with the long labor of centuries, and, not without the help of the Holy Spirit, has established a rule of language and confirmed it with the authority of the councils. This rule, which has more than once been the watchword and banner of Orthodox faith, must be religiously preserved, and let no one presume to change it at his own pleasure or under the pretext of new science. Who would ever tolerate that the dogmatic formulas used by ecumenical councils for the mysteries of the Holy Trinity and the Incarnation be judged as no longer appropriate for men of our times and therefore that others be rashly substituted for them? In the same way it cannot be tolerated that any individual should on his own authority modify the formulas which were used by the Council of Trent to express belief in the Eucharistic Mystery. For these formulas, like the others which the Church uses to propose the dogmas of faith, express concepts which are not tied to a certain form of human culture, nor to a specific phase of human culture, nor to one or other theological school.

No, these formulas present that part of reality which necessary and universal experience permits the human mind to grasp and to manifest with apt and exact terms taken either from common or polished language. For this reason, these formulas are adapted to men of all times and all places. But the most sacred task of theology is, not the invention of new dogmatic formulas to replace old ones, but rather such a defense and explanation of the formulas adopted by the councils as may demonstrate that divine Revelation is the source of the truths communicated through these expressions.

25 It must be admitted that these formulas can sometimes be more clearly and accurately explained. In fact, the achievement of this goal is highly beneficial. But it would be wrong to give to these expressions a meaning other than the original. Thus the understanding of the faith should be advanced without threat to its unchangeable truth. It is, in fact, the teaching of the First Vatican Council that "the same signification (of sacred dogmas) is to be forever retained once our Holy Mother the Church has defined it, and under no pretext of deeper penetration may that meaning be weakened." (11)

Constit. Dogm. "De Fide Cathol." c.4.


26 For the inspiration and consolation of all, we wish to review with you, venerable brothers, the doctrine which the Catholic Church has always transmitted and unanimously teaches concerning the Mystery of the Eucharist.

27 We desire to recall at the very outset what may be termed the very essence of the dogma, namely, that by means of the Mystery of the Eucharist, the Sacrifice of the Cross, which was once offered on Calvary, is remarkably re-enacted and constantly recalled, and its saving power exerted for the forgiveness of those sins which we daily commit. (12)

Cf. Concil. Trid., "Doctrina De SS. Missae Sacrificio, c.l.

28 Just as Moses with the blood of calves had sanctified the Old Testament, (Cf. Ex 24,8) so also Christ Our Lord, through the institution of the Mystery of the Eucharist, with His own Blood sanctified the New Testament, whose Mediator He is. For, as the Evangelists narrate, at the Last Supper "He took bread, and blessed and broke it, and gave it to them, saying: "This is My Body, given for you; do this for a commemoration of Me. And so with the cup, when supper was ended. This cup, he said, is the New Testament, in My Blood which is to be shed for you.'" (Lc 22,19-20; cf. Mt 26,26-28 Mc 14,22-24) And by bidding the Apostles to do this in memory of Him, He made clear His will that the same sacrifice be forever repeated.

This intention of Christ was faithfully executed by the primitive Church through her adherence to the teaching of the Apostles and through her gatherings summoned to celebrate the Eucharistic Sacrifice. As St. Luke carefully testifies, "These occupied themselves continually with the Apostles' teaching, their fellowship in the breaking of bread, and the fixed times of prayer." (Ac 2,42) From this practice, the faithful used to derive such spiritual strength that it was said of them that "there was one heart and soul in all the company of believers." (Ac 4,32)

29 Moreover, the Apostle Paul, who has faithfully transmitted to us what he had received from the Lord, (1Co 11,23ff.) is clearly speaking of the Eucharistic Sacrifice when he points out that Christians, precisely because they have been made partakers of the table of the Lord, ought not take part in pagan sacrifices. "Is not this cup we bless," he says, "a participation in Christ's Blood? Is not the Bread we break a participation in Christ's Body? ... To drink the Lord's cup, and yet to drink the cup of evil spirits, to share the Lord's feast, and to share the feast of evil spirits, is impossible for you." (1Co 10,16.) Foreshadowed by Malachias, (Ml 1,11) this new offering of the New Testament has always been offered by the Church, in accordance with the teaching of Our Lord and Apostles, "Not only to atone for the sins of the living faithful and to appeal for their other needs, but also to help these who have died in Christ but have not yet been completely purified." (20)

Concil. Trid. Doctr. De SS. Missae Sacrif. c. 2.

30 Passing over other citations, we recall merely the testimony rendered by St. Cyril of Jerusalem, who wrote the follow memorable instruction for his neophytes: "After the Spiritual Sacrifice, the unbloody act of worship has been completed. Bending over this propitiatory offering we beg God to grant peace to all the Churches, to give harmony to the whole world, to bless our rulers, our soldiers, and our companions, to aid the sick and afflicted, and in general to assist all who stand in need; and then we offer the Victim also for our deceased holy ancestors and bishops for all our dead. As we do this, we are filled with the conviction that this Sacrifice will be of the greatest help to those souls for whom prayers are being offered in the very presence of our holy and awesome Victim."

This holy Doctor closes his instruction by citing the parallel of the crown which is woven for the emperor to move him to pardon exiles: "In the same fashion, when we offer our prayers to God for the dead, even though they be sinners, we weave no crown, but instead we offer Christ slaughtered for our sins, beseeching our merciful God to take pity both on them and on ourselves." (21) At. Augustine testifies that this manner of offering also for the deceased "the Sacrifice which ransomed us" was being faithfully observed in the Church at Rome, (22) and at the same time he observes that the universal Church was following this custom in her conviction that it had been handed down by the earliest Fathers. (23)

21 Catecheses, 23 (Myst. 5), 8-18; p.g. 33, 1115-1118.
22 Cf. Confess. IX, 12, 32; P.L. 32, 777; cf. Ibid. IX, 11, 27; P.L. 32, 775.
23 Cf. Serm. 172, 2; P.L. 38, 936; cf. De Cura Gerenda Pro Mortuis, 13; P.L. 32, 775.

31 To shed fuller light on the mystery of the Church, it helps to realize that it is nothing less than the whole Church which, in union with Christ in His role as Priest and Victim, offers the Sacrifice of the Mass and is offered in it. The Fathers of the Church taught this wondrous doctrine. (24) A few years ago our predecessor of happy memory, Pius XII, explained it, (25) and only recently the Second Vatican Council enunciated it in its treatise on the People of God as formulated in its Constitution on the Church. (26)
To be sure, the distinction between universal priesthood and hierarchical priesthood is one of essence and not merely one of degree, (27) and this distinction should be faithfully observed. Yet we cannot fail to be filled with the earnest desire that this teaching on the Mass be explained over and over until it takes root deep in the hearts of the faithful. Our desire is founded on our conviction that the correct understanding of the Eucharistic Mystery is the most effective means to foster devotion to this Sacrament, to extol the dignity of all the faithfully, and to spur their spirit toward the attainment of the summit of sanctity, which is nothing less than the total offering of oneself to service of the Divine Majesty.

24 Cf. St. Augustine, De Civit. Dei, X, 6; P. L. 41, 284.
25 Cf. Litt. Encycl. Mediator Dei, A.A.S. XXXIX, 1947, p. 552.
26 Cf. Const. Dogm. De Ecclesia, C. 2,
LG 11; A.A.S. LVII, 1965, p. 15.
27 Cf. Ibid. C.2, LG 10; A.A.S. LVII, 1965, p. 14.

32 We should also mention "the public and social nature of every Mass," (28) a conclusion which clearly follows from the doctrine we have been discussing. For even though a priest should offer Mass in private, that Mass is not something private; it is an act of Christ and of the Church. In offering this Sacrifice, the Church learns to offer herself as a sacrifice for all. Moreover, for the salvation of the entire world she applies the single, boundless, redemptive power of the Sacrifice of the Cross. For every Mass is offered not for the salvation of ourselves alone, but also for that of the whole world.

Hence, although the very nature of the action renders most appropriate the active participation of many of the faithful in the celebration of the Mass, nevertheless, that Mass is to be fully approved which, in conformity with the prescriptions and lawful traditions of the Church, a priest for a sufficient reason offers in private, that is, in the presence of no one except his server. From such a Mass an abundant treasure of special salutary graces enriches the celebrant, the faithful, the whole Church, and the entire world--graces which are not imparted in the same abundance by the mere reception of Holy Communion.

28 Const. De Sacra Liturgia, C.1,
SC 27; A.A.S. LVI, 1964, p. 107.

33 Therefore, from a paternal and solicitous heart, we recommend to priests, who bestow on us a special crown of happiness in the Lord, that they be mindful of their power, received through the hands of the ordaining Bishop, of offering sacrifices to God and of celebrating Masses both for the living and for the dead in the name of the Lord, (29) and that they worthily and devoutly offer Mass each day in order that both they and the rest of the faithful may enjoy the benefits that flow so richly from the Sacrifice of the Cross. Thus also they will contribute most to the salvation of the human race.

29 Cf. Pontifice Romanum.


34 By the few ideas which we have mentioned regarding the Sacrifice of the Mass, we are encouraged to explain a few notions concerning the Sacrament of the Eucharist, seeing that both sacrifice and Sacrament pertain inseparably to the same mystery. In an unbloody representation of the Sacrifice of the Cross and in application of its saving power, in the Sacrifice of the Mass the Lord is immolated when, through the words of consecration, He begins to be present in a sacramental form under the appearances of bread and wine to become the spiritual food of the faithful.

35 All of us realize that there is more than one way in which Christ is present in His church. We wish to review at greater length the consoling doctrine which was briefly set forth in the constitution "De Sacra Liturgia." (30) Christ is present in His Church when she prays, since it is He who "prays for us and prays in us and to whom we pray as to our God." (31) It is He who has promised: "Where two or three are gathered together in My name, I am there in the midst of them." (Mt 18,20) He is present in the Church as she performs her works of mercy, not only because we do to Christ whatever good we do to one of His least brethren, (Cf. Mt 25,40) but also because it is Christ, performing these works through the Church, who continually assists men with His divine love. He is present in the Church on her pilgrimage of struggle to reach the harbor of eternal life, since it is He who through faith dwells in our hearts (Cf. Ep 3,17) and, through the Holy Spirit whom He gives us, pours His love into those hearts. (Cf. Rm 5,5)

30 Cf. C.1, SC 7; A.A.S. LVI, 1964, pp. 100-101.
31 St. Augustine, "In Ps " 85, 1; P.L. 37, 1081.

36 In still another genuine way He is present in the Church as she preaches, since the Gospel which eh proclaims is the Word of God, which is not preached except in the name of Christ, by the authority of Christ, and with the assistance of Christ, the Incarnate Word of God. In this way there is formed "one flock which trusts its only shepherd." (36)

36 Idem, "Contr. Litt. Petiliani" III, 10, 11; P.L. 43, 353.

37 He is present in His Church as she governs the People of God, since her sacred power comes from Christ, and since Christ, "The Shepherd of Shepherds," (37) is present in the pastors who exercise that power, according to His promise to the Apostles: "Behold I am with you all through the days that are coming, until the consummation of the world."

37 St. Augustine, "In Ps " 86, 3; P.L. 37, 1102.

38 Moreover, in a manner still more sublime, Christ is present in His Church as she offers in His name the Sacrifice of the Mass; He is present in her as she administers the sacraments. We find deep consolation in recalling the accurate and eloquent words with which St. John Chrysostom overcome with a sense of awe, described the presence of Christ in the offering of the Sacrifice of the Mass: "I wish to add something that is plainly awe-inspiring, but do not be astonished or upset. This Sacrifice, no matter who offers it, be it Peter or Paul, is always the same as that which Christ gave His disciples and which priests now offer: The offering of today is in no way inferior to that which Christ offered, because it is not men who sanctify the offering of today; it is the same Christ who sanctified His own. For just as the words which God spoke are the very same as those which the priest now speaks, so too the oblation is the very same." (38) No one is unaware that the sacraments are the actions of Christ, who administers them through men. Therefore, the sacraments are holy in themselves, and by the power of Christ they pour grace into the soul when they touch the body. The mind boggles at these different ways in which Christ is present; they confront the Church with a mystery ever to be pondered.

But there is yet another manner in which Christ is present in His Church, a manner which surpasses all the others; it is His presence in the Sacrament of the Eucharist, which is for this reason «a more consoling source of devotion, a more lovely object of contemplation, a more effective means of sanctification than all the other sacraments." (39) The reason is clear; it contains Christ Himself and it is "a kind of perfection of the spiritual life; in a way, it is the goal of all the sacraments." (40)

38 "In Epist. 2 Ad Timoth. Homil." 2,4; P.G. 62, 612.
39 Aegidius Romanus, "Theoremata De Corpore Christ," Theor. 50, Venetiis 1521, p. 127.
40 St. Thomas,
III 73,3 C.

39 This presence is called "real"--by which it is not intended to exclude all other types of presence as if they could not be "real" too, but because it is presence in the fullest sense: that is to say, it is a substantial presence by which Christ, the God-Man, is wholly and entirely present. (41) It would therefore be wrong to explain this presence by having recourse to the "spiritual" nature, as it is called, of the glorified Body of Christ, which is present everywhere, or by reducing it to a kind of symbolism, as if this most august Sacrament consisted of nothing else than an efficacious sign, «of the spiritual presence of Christ and of His intimate union with the faithful, members of His Mystical Body." (42)

41 Cf. Conc. of Trent, Decree on the Eucharist, Chr. 3.
42 Pius XII, Encycl. Humani Generis, A.A.S. XLII, 1950, p. 578.

40 It is true that much can be found in the Fathers and in the scholastics with regard to the symbolism of the Eucharist, especially with reference to the unity of the Church. The Council of Trent, restating their doctrine, taught that the Savior bequeathed the blessed Eucharist to His Church "as a symbol ... of that unity and charity with which He wished all Christians to be most intimately united among themselves," and hence "as a symbol of that One Body of which He is the Head." (43)

43 Decree "On the Eucharist," Proem, and Ch. 2.

41 When Christian literature was still in its infancy, the unknown author of that work we know as the Didache or Teaching of the Twelve Apostles" wrote as follows on this subject: "In regard to the Eucharist, give thanks in this manner: ... just as this bread was scattered and dispersed over the hills, but when harvested was made one, so may Your Church be gathered into Your kingdom from the ends of the earth." (44)

44 "Didache," 9,1 Funk, "Patres Apostolici," 1,20.

42 The same we read in St. Cyprian, writing in defense of the Church against schism: "Finally, the sacrifices of the Lord proclaim the unity of Christians, bound together by the bond of a firm and inviolable charity. For when the Lord, in speaking of bread which is produced by the compacting of many grains of wheat, refers to it as His Body, He is describing our people whose unity He has sustained, and when He refers to wine pressed from many grapes and berries, as His Blood, He is speaking of our flock, formed by the fusing of many united together." (45)

45 "Ep. Ad Magnum," 6; P. L. 3, 1189.

43 But before all of these, St. Paul had written to the Corinthians: the one bread makes us one body, though we are many in number the same bread is shared by all. (1Co 10,17)

44 While the eucharistic symbolism brings us to an understanding of the effect proper to this Sacrament, which is the unity of the mystical Body, it does not indicate or explain what it is that makes this Sacrament different from all others. The constant teaching which the Catholic Church passes on to her catechumens, the understanding of the Christian people, the doctrine defined by the Council of Trent, the very words used by Christ when He instituted the Most Holy Eucharist, compel us to acknowledge that "the Eucharist is that flesh of Our Savior Jesus Christ who suffered for our sins and whom the Father in His loving-kindness raised again." (

47 St. Ignatius, "Ep. Ad Smyrn." 7,1; P. G. 5, 714.
48 "In Matth. Comm.," Ch. 26 P. G. 66, 714.

45 The Council of Trent, basing itself on this faith of the Church, «openly and sincerely professes that within the Holy Sacrament of the Eucharist, after the Consecration of the bread and wine, Our Lord Jesus Christ, true God and true Man, really, truly and substantially contained under those outward appearances." In this way, the Savior in His humanity is present not only at the right hand of the Father according to the natural manner of existence, but also in the Sacrament of the Eucharist "by a mode of existence which we cannot express in words, but which, with a mind illumined by faith, we can conceive, and must most firmly believe, to be possible to God." (49 )

49 Decree "On the Eucharist," Ch. 1.


46 To avoid misunderstanding this sacramental presence which surpasses the laws of nature and constitutes the greatest miracle of its kind (50) we must listen with docility to the voice of the teaching and praying Church. This voice, which constantly echoes the voice of Christ, assures us that the way Christ is made present in this Sacrament is none other than by the change of the whole substance of the bread into His Body, and of the whole substance of the wine into His Blood, and that this unique and truly wonderful change the Catholic Church rightly calls transubstantiation. (51) As a result of transubstantiation, the species of bread and wine undoubtedly take on a new meaning and a new finality, for they no longer remain ordinary bread and ordinary wine, but become the sign of something sacred, the sign of a spiritual food. However, the reason they take on this new significance and this new finality is simply because they contain a new "reality" which we may justly term ontological. Not that there lies under those species what was already there before,, but something quite different; and that not only because of the faith of the Church, but in objective reality, since after the change of the substance or nature of the bread and wine into the Body and Blood of Christ, nothing remains of the bread and wine but the appearances under which Christ, whole and entire, in His physical "reality" is bodily present, although not in the same way that bodies are present in a given place.

50 Cf. Encycl. Mirae Caritatis, Acta Leonis XIII, Vol. XXII, 1902-1903, p. 123.
51 Cf. Council of Trent, "Decree on the Eucharist," Ch. 4, and Can. 2.

47 For this reason the Fathers took special care to warn the faithful that in reflecting on this most august Sacrament, they should not trust to their senses, which reach only the properties of bread and wine, but rather to the words of Christ which have power to transform, change and transmute the bread and wine into His Body and Blood. For, as those same Fathers often said, the power that accomplishes this is that same power by which God Almighty, at the beginning of time, created the world out of nothing.

48 "We have been instructed in these matters and filled with an unshakable faith," says St. Cyril of Alexandria, at the end of a sermon on the mysteries of the faith, "that that which seems to be bread, is not bread, though it tastes like it, but the Body of Christ, and that which seems to be wine, is not wine, though it too tastes as such, but the Blood of Christ ... draw inner strength by receiving this bread as spiritual food and your soul will rejoice." (52)

52 "Catecheses," 22, 9; "Myst." 4; P. G. 33, 1103.

49 St. John Chrysostom emphasizes this point, saying: "It is not the power of man which makes what is put before us the Body and Blood of Christ, but the power of Christ Himself who was crucified for us. The priest standing there in the place of Christ says these words but their power and grace are from God. 'This is My Body,' he says, and these words transform what lies before him." (53)

53 "De Prodit. Iudae. Homil." 1,6; P.G. 49, 380; cf. "In Matth. Homil." 82,5; P.G. 58, 744.

50 Cyril, Bishop of Alexandria, is in full agreement with the Bishop of Constantinople when he writes in his commentary on the Gospel of St. Matthew: "Christ said indicating (the bread and wine): 'This is My Body,' and "This is My Blood," in order that you might not judge what you see to be a mere figure. The offerings, by the hidden power of God Almighty, are changed into Christ's Body and Blood, and by receiving these we come to share in the life-giving and sanctifying efficacy of Christ." (54)

54 "In Matth." 26,27; P.G. 72, 451.

51 Ambrose, Bishop of Milan, dealing with the Eucharistic change, says: "Let us be assured that this is not what nature formed, but what the blessing consecrated, and that greater efficacy resides in the blessing than in nature, for by the blessing nature is changed." To confirm the truth of this mystery, he recounts many of the miracles described in the Scriptures, including Christ's birth of the Virgin Mary, and then turning to the work of creation, concludes thus: "Surely the word of Christ, which could make out of nothing that which did not exist, can change things already in existence into what they were not. For it is no less extraordinary to give things new natures than to change their natures." (55)

55 "De Myster." 9, 50-52; P.L. 16, 422-424.

52 However, there is no need to assemble many testimonies. Rather let us recall that firmness of faith with which the Church with one accord opposed Berengarius, who, yielding to the difficulties of human reasoning, was the first who denied the Eucharistic change. More than once she threatened to condemn him unless he retracted. Thus it was that our predecessor, St. Gregory VII, ordered him to pronounce the following oath:

"I believe in my heart and openly profess that the bread and wine which are placed upon the altar are, by the mystery of the sacred prayer and the words of the Redeemer, substantially changed into the true and life-giving flesh and blood of Jesus Christ Our Lord, and that after the Consecration, there is present the true Body of Christ which was born of the Virgin and, offered up for the salvation of the world, hung on the Cross and now sits at the right hand of the Father, and that there is present the true Blood of Christ which flowed from His side. They are present not only by means of a sign and of the efficacy of the Sacrament, but also in the very reality and truth of their nature and substance." (56)

56 Mansi, "Coll. Ampliss. Concil." XX, 524D.

53 These words fully accord with the doctrine of the mystery of the Eucharistic change as set forth by the ecumenical councils. The constant teaching of these councils--of the Lateran, of Constance, Florence and Trent--whether stating the teaching of the Church or condemning errors, affords us an admirable example of the unchangingness of the Catholic Faith.

54 After the Council of Trent, our predecessor, Pius VI, on the occasion of the errors of the Synod of Pistoia, warned parish priests when carrying out their office of teaching, not to neglect to speak of transubstantiation, one of the articles of faith. (57) Similarly our predecessor of happy memory, Pius XII, recalled the bounds which those who undertake to discuss the mystery of transubstantiation might not cross. (58) We ourself also, in fulfillment of our apostolic office, have openly borne solemn witness to the faith of the Church at the National Eucharistic Congress held recently at Pisa. (59)

57 Const. "Auctorem Fidei," 28 August 1794.
58 Allocutio Habita Die 22 Septembris 1956, A.A.S. CLVIII, 1956, p. 720.
59 A.A.S. LVII, 1965, pp. 588-592.

55 Moreover the Catholic Church has held on to this faith in the presence in the Eucharist of the Body and Blood of Christ, not only in her teaching but also in her practice, since she has at all times given to this great Sacrament the worship which is known as Latria and which may be given to God alone. As St. Augustine says: "It was in His flesh that Christ walked among us and it is His flesh that He has given us to eat for our salvation. No one, however, eats of this without having first adored it ... and not only do we not sin in thus adoring it, but we would sin if we did not do so." (60 )

60 "In Ps " 98, 9; P.L. 37, 1264.

Mysterium Fidei EN