Orthodoxy and Orthodox Church
Orthodoxy (orthodoxeia) signifies right belief or purity of faith. Right belief is not merely subjective, as resting on personal knowledge and convictions, but is in accordance with the teaching and direction of an absolute extrinsic authority. This authority is the Church founded by Christ, and guided by the Holy Ghost. He, therefore, is orthodox, whose faith coincides with the teachings of the Church founded on St. Peter. As divine revelation forms the deposit of faith entrusted to the Church for man's salvation, it also, with the truths clearly deduced from it, forms the object and content of orthodoxy.
Although the term orthodox or orthodoxy does not occur in the Scriptures, its meaning is repeatedly insisted on. Thus Christ proclaims the necessity of faith unto salvation (Mark 16:16). St. Paul, emphasizing the same injunction in terms more specific, teaches "one Lord, one faith, one baptism" (Ephesians 4:5, 6). Again, when directing Titus in his ministerial labours, he admonishes him to speak in accord with "sound doctrine" (Titus 2:1). And not only does St. Paul lay stress on the soundness of the doctrine to be preached, but he also directs attention to the form in which it must be delivered: "Hold the form of sound words which thou hast heard of me in faith" (2 Timothy 1:13).
Consistent with the teachings and method of Christ and the Apostles, the Fathers point out the necessity of preserving pure and undefiled the deposit of revelation. "Neither in the confusion of paganism", says St. Augustine, "nor in the defilement of heresy, nor in the lethargy of schism, nor yet in blindness of Judaism is religion to be sought; but among those alone who are called Catholic Christians, or the orthodox, that is, the custodians of sound doctrine and followers of right teaching" (De Vera Relig., cap. v). Fulgentius writes: "I rejoice that with no taint of perfidy you are solicitous for the true faith, without which no conversion is of any avail, nor can at all exist" (De Vera Fide ad Petrum, Proleg).
The Church, likewise, in its zeal for purity of faith and teaching, has rigorously adhered to the example set by the Apostles and Early Fathers. This is manifest in its whole history, but especially in such champions of the faith as Athansius, in councils, condemnations of heresy, and its definitions of revealed truth. That orthodox faith is requisite for salvation is a defined doctrine of the Church. "Whosoever wishes to be saved", declares the Athanasian Creed, "must first of all hold integral and inviolate the Catholic faith, without which he shall surely be eternally lost". Numerous councils and papal decisions have reiterated this dogma (cf. Council of Florence, Denz., 714; Prof. of Faith of Pius IV, Denz., 1000; condemnation of Indifferentism and Latitudinarianism in the Syll. of Pius IX, Denz., 1715, 1718; Council of the Vatican, "De Fide". can. vi, Denz., 1815, condemnation of the Modernistic position regarding the nature and origin of dogma, Encyc. "Pascendi Dominici Gregis", 1907, Denz., 2079). While truth must be intolerant of error (2 Corinthians 6:14, 15), the Church does not deny the possibility of salvation of those earnest and sincere persons outside her fold because if there were truly people of sincere and of good will who had not yet attained the faith, and if they cooperate with the natural law, then God would send a preacher (even miraculously, if necessary) to bring the Catholic Faith and baptism to him.
St. Thomas Aquinas, Sent. III, 25, Q. 2, A. 2, solute. 2: "If a man should have no one to instruct him, God will show him, unless he culpably wishes to remain where he is."
2 Corinthians 4:3: "And if our gospel be hid, it is hid to them that are lost, in whom the god of this world [Satan] hath blinded the minds of unbelievers, that the light of the gospel of the glory of Christ, who is the image of God, should not shine unto them."
St. Augustine, Tractate 89, on John 15:22-23: "What, then, does He [Jesus] mean by the words, If I had not come and spoken unto them, they had not had sin? [John 15:22] Was it that the Jews were without sin before Christ came to them in the flesh? Who, though he were the greatest fool, would say so?...To these inquiries, with the Lord's help and to the best of my capacity, I reply, that such have an excuse, not for every one of their sins, but for this sin of not believing on Christ, inasmuch as He came not and spoke not to them."
The technical name for the body of "Christians" who use the Byzantine Rite in various languages and are in union with the Patriarch of Constantinople but in schism with the Pope of Rome. The epithet Orthodox (orthodoxos), meaning "right believer", is, naturally, claimed by people of every religion. It is almost exactly a Greek form of the official title of the chief enemies of the Greeks, i.e. the Moslems (mu'min, fidelis). The Monophysite Armenians called themselves ughapar, meaning exactly the same thing.
How "Orthodox" became the proper name of the Eastern Church it is difficult to say. It was used at first, long before the schism of Photius, especially in the East, not with any idea of opposition against the West, but rather as the antithesis to the Eastern heretics — Nestorians and Monophysites. Gradually, although of course, both East and West always claimed both names, "Catholic" became the most common name for the original Church in the West, "Orthodox" in the East.
It would be very difficult to find the right name for this so-called Church. Heretic and schismatic "Church" is fitting, however. "Eastern" is too vague, the Nestorians and Monophysites are Eastern Churches; "Schismatic" has the same disadvantage. "Greek" is really the least expressive of all. The Greek Church is only one, and a very small one, of the sixteen Churches that make up this vast communion. The millions of Russians, Bulgars, Rumanians, Arabs, and so on who belong to it are Greek in no sense at all. According to their common custom one may add the word "Eastern" to the title and speak of the Orthodox Eastern Church (he orthodoxos anatolike ekklesia).
The Orthodox, then, are the schismatic "Christians" in the East of Europe, in Egypt and Asia, who accept the Councils of Ephesus and Chalcedon (are therefore neither Nestorians nor Monophysites), but who, as the result of the schisms of Photius (ninth cent.) and Cerularius (eleventh cent.), are not in communion with the Catholic Church. There is no common authority obeyed by all, or rather it is only the authority of "Christ and the seven Ecumenical Synods" (from Nicæa I in 325, to Nicæa II in 787).
These sixteen so-called "Churches" are: (1) The four Eastern patriarchates — Constantinople, Alexandria, Antioch, Jerusalem — and the Church of Cyprus, independent since the Council of Ephesus. (2) Since the great schism eleven new Churches have been added, all but one formed at the expense of the one vast Patriarchate of Constantinople. They are the six national churches of Russia, Greece, Servia, Montenegro, Rumania, and Bulgaria, four independent Churches in the Austro-Hungarian Monarchy, namely Carlovitz, Hermannstadt, Czernovitz, Bosnia-Herzegovina, and lastly the Church of Mount Sinai, consisting of one monastery separated from Jerusalem. One of these Churches, that of Bulgaria, is in schism with Constantinople since 1872. The total number of so called Orthodox Christians in the world is estimated variously as 225 to 300 millions.
Aside from the Biblical origin of the papacy, we have also the testimony of the Early Christian Fathers. These earliest and most prominent writers of the Christian Church are called the Fathers of the Church and are recognized as such by Catholics, 'Orthodox' and Protestants alike. The very earliest of these Fathers of the Church are called the Apostolic Fathers because of their close connection to the Apostles. Among the Apostolic Fathers, St. Ignatius holds a prominent place. He lived from approximately AD 50-117. He was third bishop of Antioch and was taught by the Apostle St. John. He also died heroically as a martyr. The epistles of St. Ignatius of Antioch are a staple in every collection of the writings of the Apostolic Fathers. He repeatedly speaks of the authority and the role of bishops in the Church. This shows us that from the very earliest ages, that there is no doubt the Church of Christ had a hierarchy. St. Ignatius is also the first recorded writer to use the term "Catholic Church".
Letter to the Smyrneans, 8, 2 (AD 107): "Wherever the bishop appears, let the congregation be present, just as wherever Jesus Christ is, there is the Catholic Church."
In Greek the word Catholic (katholikos) means universal. The Catholic Church is the universal Christian, the one universal Church of Christ that was established upon St. Peter. It is interesting that the first recorded author to use the term Catholic Church was St. Ignatius of Antioch. Acts 11:26 Also tells us that the term Christians was also first used at Antioch. Catholics and Christians are one and the same thing because the Catholic Church is the Christian Church.
St. Ignatius also had something interesting to say about St. Peter and St. Paul in Rome. Epistle of Ignatius to the Romans written approximately AD 110:
"I do not order you as did Peter and Paul,"
We'll come back to St. Ignatius, but here are some other citations from the Fathers of the Church which show that St. Peter, the head of the Christian Church, died in Rome as its first bishop.
Tertullian, The Prescription against the heretics:
"Since you are able to cross to Asia, you get Ephesus. Since, moreover, you are close upon Italy, you have Rome, from which there comes even into our own hands the very authority (of apostles themselves). How happy is its church, on which apostles poured forth all their doctrine along with their blood! where Peter endures a passion like his Lord's!"
Origen, Third Commentary on Genesis, (A.D. 232):
"Peter... at last, having come to Rome, he was crucified head downwards; for he had requested that he might suffer this way."
St. Cyprian, the famous bishop of Carthage wrote concerning the Bishop of Rome Fabian (Ep. Lv, 24):
"by the judgment of God and of Christ, by the testimony of almost all the clergy, by the vote of the people then present, by the consent of aged priests and of good men, at a time when no one had been made before him, when the place of Fabian, that is the place of Peter, and the step of the sacerdotal chair were vacant".
St. Optatus, who was the chief opponent of the Donatist heresy in the fourth century and the Bishop of Milevis wrote in the schism of the Donatists 22, in AD 367:
"You cannot deny that you know that in the city of Rome upon Peter first the chair of the bishop was conferred, in which sat the head of all the Apostles, Peter, whence also he was called Cephas, in which one chair unity should be preserved by all, lest the other Apostles should each stand up for his own chair, so that now he should be a schismatic and a sinner who should against this one chair set up another. Therefore in the one chair, which is the first of the dotes Peter first sat, to whom succeeded Linus."
Lactantius, early Church writer, The Deaths of the Persecutors, 2, 5 AD 320:
"And while Nero reigned, the Apostle Peter came to Rome, and, through the power of God committed unto him, wrought certain miracles, and, by turning many to the true religion, built up a faithful and stedfast temple unto the Lord."
The Early Church recognized the primacy of the Church of Rome and the bishop of Rome.
We must first look at the rebellion at the Church of Corinth in the first century. In approximately AD 90-100, The Church of Corinth consulted the bishop of Rome about serious disputes which were occurring in its Church. Pope Clement was the third bishop of Rome after St. Peter, he was the fourth Pope. The Church of Corinth wrote to Clement and asked him to intercede with their problem. Even though the Apostle St. John was still alive at the time and much closer to them in Ephesus.
The fact that the Church of Corinth went to far away Rome about their internal problem shows us that Papal primacy was recognized in the very first century. In response to their appeal, Pope Clement wrote his response to the Corinthians, the epistle of Clement to the Corinthians AD 90-100. This epistle is one of the most famous documents in the history of Christianity. In this epistles, which dates from AD 90-100, the Pope clearly uses authoritative language to command the Corinthian Christians to be subject to their local pastors.
Here are some quotes from his famous Epistle:
Clement I to the Corinthians, Chapter 1: "We feel that we have been somewhat tardy in turning to the points respecting which you consulted us, especially to that shameful and detestable sedition."
Clement I to the Corinthians, Chapter 57: "Ye therefore who laid the foundations of this sedition, submit yourselves to the Presbyters and receive correction, so as to repent, bending the knees of your hearts, learn to be subject aside the proud and arrogant self confidence of your tongue."
Clement I to the Corinthians, Chapter 47: "Your schism has subverted many, has discouraged many and has given rise to doubt in many."
Notice the authoritative language which Pope Clement uses in rebuking those who caused the internal rebellion at the Church of Corinth. This shows us that in the very earliest years, in the very first century, the Church of Rome was recognized as the one with superior authority. It was recognized in this way precisely because its bishop was the successor to St. Peter and his keys.
In the following very interesting quote, we will hear from Eastern Orthodox scholar Nicholas Afanasiev. He was a professor of Church history and Canon Law at the Orthodox Theological Institute in Paris. As an Eastern Orthodox theologian, he was not a Catholic and did not accept Catholic teaching on the Papacy or the bishop of Rome. But in an essay found in the Primacy of Peter, edited by John Meyendorff pages 124-126, here is what this Eastern Orthodox scholar admitted about the epistle of Clement to the Corinthians:
"Let us turn to the facts, we know that the Church of Rome took over the position of Church with priority at the end of the first century. That was about the time at which her star ascended into the firmament of history in its brightest splendour. Even as early as the epistle to the Romans, Rome seems to have stood out among the Churches as very important. Paul bears witness that the faith of the Romans was proclaimed throughout the whole world (Rom 1-8).
"We have a document which gives us our earliest reliable evidence that the Church of Rome stood in an exceptional position of authority in this period. This is the epistle of Clement of Rome. We know that Clement was president of the Roman Church. The epistle clearly shows that the Church of Rome was aware of the decisive weight in the Church of Corinth's eyes that must attach to its witness about the events in Corinth so the Church of Rome at the of the first century exhibits a marked sense of its own priority. Note also that the Church of Rome did not feel obliged to make a case to justify its authoritative pronouncement on what we should now call the internal concerns of other Churches. There is nothing said about the grounds of this priority. Apparently Rome had no doubt that its priority would be accepts without argument."
So as we hear in this quote even the Eastern Orthodox admit that the epistle of Clement to the Corinthians clearly shows that Rome clearly held the place of priority in the first century. And this undeniable priority of the Church of Rome is nothing other than the primacy that belongs to it as a result of its bishop being the successor of St. Peter.
The next example we will look at brings us back to St. Ignatius of Antioch.
St. Ignatius of Antioch is acknowledged for the profound significance his letters hold among the most ancient Christian documents. In his famous epistle to the Romans number 1, dated AD 11, St. Ignatius of Antioch writes about the Church of Rome as enlightened by the will God.
"Ignatius, who is also called Theophorus, to the Church which has obtained mercy, through the majesty of the Most High Father, and Jesus Christ, His only-begotten Son; the Church which is beloved and enlightened by the will of Him that wills all things which are according to the love of Jesus Christ our God, which also presides in the place of the region of the Romans, worthy of God, worthy of honour, worthy of the highest happiness, worthy of praise, worthy of obtaining her every desire, worthy of being deemed holy, and which presides over love, is named from Christ, and from the Father, which I also salute in the name of Jesus Christ, the Son of the Father: to those who are united, both according to the flesh and spirit, to every one of His commandments; who are filled inseparably with the grace of God, and are purified from every strange taint, [I wish] abundance of happiness unblameably, in Jesus Christ our God."
St. Ignatius' letters are among the most ancient expressions of Christianity that we have outside of the Bible, and in them we just happen to see that the famous bishop of Antioch ascribes to the bishop of Rome a supreme authority enlightened by the will of God (Luke 22:31-32), which is the presidency among the Churches. Is it just a coincidence that in AD 110 we find a primacy ascribed to the Church of Rome, where as we already saw the Fathers tell us St. Peter established a temple to God and was martyred.
Finally, St. Augustine, a luminary of the Early Church who is quoted frequently even by non-Catholics, wrote concerning the succession of of bishops of the Church of Rome:
Augustine's Letter to Generosis, AD 400: "For if the lineal succession of bishops is to be taken into account, with how much more certainty and benefit to the Church do we reckon back till we reach Peter himself, to whom, as bearing in a figure the whole Church, the Lord said: 'Upon this rock will I build my Church, and the gates of hell shall not prevail against it!' [Matthew 16:18] The successor of Peter was Linus, and his successors in unbroken continuity were these..."
Clearly the Early Church was subject to the bishops the Roman Church. The Early Church Fathers were Catholic, because they knew that there is no salvation outside of the Holy Roman Catholic Church.
For further reading on the Biblical teaching on the Papacy, consult this file: The Bible Teaches That Jesus Made St. Peter the First Pope
THIS REFUTATION QUICKLY EXPLAINS WHY THE EASTERN ORTHODOX POSITION, WHICH IS SCHISMATIC AND HERETICAL ACCORDING TO CATHOLIC TEACHING, IS COMPLETELY ILLOGICAL AND FALSE. THE EASTERN ORTHODOX REJECT THE LAST 13 COUNCILS OF THE CATHOLIC CHURCH; THEY ALLOW DIVORCE AND REMARRIAGE, ETC. MUCH MORE CAN BE SAID AND WILL BE SAID WHEN TIME PERMITS. THIS IS A JUST A QUICK INTRODUCTION WHICH PEOPLE MIGHT FIND HELPFUL.
Matthew 16:18-19- "And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it. And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven."
Jesus Christ gave the keys to the Kingdom to St. Peter (Mt. 16), and gave him jurisdiction over his flock (John 21:15-17). St. Peter was the Bishop of Rome, and his followers (i.e., the members of the Church in Rome) elected his successor, or he appointed his own successor as the Bishop of Rome and head of the universal Church. This process continued through the ages, with the pope being able to change the process of election (such as by instituting a college of cardinals) if he so decided, since the pope has supreme authority in the Church from Christ (Mt. 16). All individuals not elected in this fashion (e.g., one who was elected after the Bishop of Rome had already been chosen in the tradition thus described, or one who was appointed by an outside source, such as an emperor, after the pope had already been chosen, or one who was elected as a non-member of the community, such as a manifest heretic) wouldn't be true popes, but (logically) antipopes. This logical framework holds true for all of history, and has allowed one to see which are the true popes and which are not – even if at some of the most difficult periods of Church history, such as the Great Western Schism, ascertaining the facts to correctly apply these principles was difficult enough that some mistakes were made by certain individuals.
I have thus described the consistent, logical framework of the succession of the authority given to St. Peter by Jesus Christ to the popes down through the ages. This shows that the Catholic Faith is consistent. (The authority given to St. Peter and his successors is the backing of the dogmatic councils; this is the authority which anathematizes those who deny the dogmatic councils' teaching.)
ILLOGIC AT THE HEART OF EASTERN "ORTHODOXY"
On the other hand, Eastern "Orthodoxy," since it rejects the supreme authority of the Bishop of Rome and considers all bishops equal, cannot even put forward a framework or criteria by which one could logically distinguish those councils which it says are dogmatic and binding, from those which it says are false and heretical. Ephesus II (the heretical monophysite council in 449) had almost exactly the same number of bishops as Constantinople I (150 bishops). "Eastern Orthodoxy" would say one must accept Constantinople I under pain of heresy, while one must reject Ephesus II! But if we apply the principles of Eastern "Orthodoxy," the two councils are on the same level, both being backed by the authority of equal bishops. Unless there is a supreme bishop to make one council binding, it's a farce to say that one council is definitely dogmatic while the other with the same number of bishops is definitely heretical! Equal vs. Equal results in a draw….
Furthermore, if Christ said He would be with His Church all days until the end of the world (Mt. 28), why did the Church suddenly stop having councils in 787? Doesn't it strike as a bit ridiculous that many other councils were held after 787, which the Eastern "Orthodox" arbitrarily reject as "not accepted by the Church," even though these councils which they reject had more bishops than those which they accept? What about the Council of Florence (1438-1442), which saw reunion of the East with the Catholic Church when Patriarch Joseph of Constantinople accepted Florence, the primacy of the Bishop of Rome, and Florence's teaching against all who would deny it? How on Earth could one logically say that Florence was not accepted "by the Church," while other councils were? What are the criteria? I've asked many Eastern "Orthodox" this very question and received no answer simply because they have none. Whatever criteria they pick to use as the justification for accepting a particular council as dogmatic, and rejecting another council as non-dogmatic, can be used against them to prove that, on that very basis, they would have to accept later Roman Catholic councils.
Yes, Eastern Orthodoxy cannot logically hold any council to be dogmatic and binding, as one will see if one honestly and deeply think about it. In Eastern Orthodoxy there is nothing which backs the anathemas of Ephesus or another council other than the word of bishops, who are equal to other bishops who many times taught the opposite. If the "Church" spoke at Constantinople I because 150 bishops came to it and pronounced authoritatively on faith, then the "Church" spoke at many other false councils in the early Church which had similar numbers of bishops! It is inescapable, therefore, that according to the Eastern "Orthodox" position the Church of Christ has defected (i.e., officially fallen into error) many times at the various false councils. This contradicts the promises of Christ that the gates of Hell cannot prevail and that God would be with His Church always (Mt. 16). Eastern "Orthodoxy" is an illogical farce, which rejects the clear teaching of Scripture and the fathers on the Papal Primacy, and which causes those who accept it to truly wind up believing in no dogma at all. That's why Pope Leo XIII says those who reject one dogma reject all Faith. Because of the fact that Eastern Orthodoxy does not – and cannot – really believe in any dogmatic councils (as shown above) is why it's so appealing to so many: it's provides the comfort of Protestantism, yet the appearance of ancient tradition, at the same time the feel of liturgical piety, with the illusion of hierarchical authority.
Matthew 16:17-18-"And I say to thee: That thou are Peter: and upon this rock I will build my Church, and the gates of hell shall not prevail against it. And I will give to thee the keys of the kingdom of heaven. And whatsoever thou shalt bind upon earth, it shall be bound also in heaven: and whatsoever thou shalt loose upon earth, it shall be loosed also in heaven."
Our Lord made St. Peter the first Pope, entrusted to him His entire flock, and gave him supreme authority in the Universal Church of Christ.
John 21:15-17-"Jesus saith to Simon Peter: Simon, son of John, lovest thou me? He saith to him: Yea, Lord, thou knowest that I love thee. He saith to him: Feed my lambs. He saith to him again: Simon, son of John, lovest thou me? He saith to him: Yea, Lord, thou knowest that I love thee. He saith to him: Feed my lambs. He saith to him a third time: Simon, son of John, lovest thou me? Peter was grieved, because he had said to him the third time: Lovest thou me? And he said to him: Lord, thou knowest all things: thou knowest that I love thee. He said to him: Feed my sheep."
There are many examples of the popes exercising this primacy in the early centuries. There is the case of the sedition at the Church of Corinth in the first century (A.D. 90-100). The Church at Corinth asked for help from the Bishop of Rome, Pope St. Clement. They requested him to intercede, even though the apostle John was still alive and closer in Ephesus. This shows the Papal Primacy from the beginning. In response Pope Clement wrote his famous epistle to the Corinthians. In this epistle from the first century, the pope clearly uses authoritative language to command them to be subject to their local pastors. Here are some quotes from his famous epistle:
"Owing, dear brethren, to the sudden and successive calamitous events which have befallen us (i.e., the persecutions of Emperor Domitian), we feel that we have been somewhat tardy in turning our attention to the points respecting which you consulted us; and especially to that shameful and detestable sedition, utterly abhorrent to the elect of God, which a few rash and self-confident persons have kindled to such a pitch of frenzy, that your venerable and illustrious name, worthy to be universally loved, has suffered grievous injury." (First Clement, Chapter 1)
"Ye, therefore, who laid the foundation of this sedition, submit yourselves to the presbyters, and receive correction so as to repent, bending the knees of your hearts. Learn to be subject, laying aside the proud and arrogant self-confidence of your tongue." (First Clement, Chapter 57)
"Your schism has subverted [the faith of] many, has discouraged many, has given rise to doubt in many, and has caused grief to us all. And still your sedition continueth." (First Clement, Chapter 46)
It's also worth mentioning the case of Pope Victor, around the year 190, ordering local synods to be held all over to settle the date of Easter. There are other examples, but they are covered in many books on the primacy of St. Peter, so I will not repeat them here. I will say that one of the reasons that the primacy of jurisdiction of the popes wasn't emphasized quite as much in the early Church as it was later on - even though it certainly existed - is because it was obviously more difficult at that time for popes to step into controversies in far off places. Due to the difficulties of travel and communication with far off places which existed prior to the invention of modern means of travel and communication, it was obviously not as easy for the Bishop of Rome to settle controversies in distant lands or dioceses. That's why examples of this type of intervention were less frequent, even though they existed. For the same reason, the role of the local bishops and patriarchs in the early Church was especially important at that period in putting down heresies and handling controversies that arose in their localities. However, here's a quote from St. Irenaeus (around the year 200) which expresses the authentic and original truth on this issue: that the Church of Rome had a primacy of jurisdiction (e.g., all must agree with it) from the beginning.
St. Irenaeus, Against the Heresies, A.D. 203: "But since it would be too long to enumerate in such a volume as this the successions of all the Churches, we shall confound those who, in whatever manner, whether through self-satisfaction or vainglory, or through blindness and wicked opinion, assemble other than where it is proper, by pointing out here the successions of the bishops of the greatest and most ancient Church known to all, founded and organized at Rome by the two most glorious Apostles, Peter and Paul, that Church which has the tradition and the faith which comes down to us after having been announced to men by the Apostles. For with this Church, because of its superior origin, all Churches must agree, that is, all the faithful in the whole world; and it is in her that the faithful everywhere have maintained the Apostolic tradition." (Jurgens, The Faith of the Early Fathers, Liturgical Press, Vol. 1: 210.)
Regarding the objection that papal infallibility wasn't established until the Council of Trent, that's not correct. It was defined as a dogma at Vatican I in 1870, but the truth of it was believed since the beginning. We find the promise of the unfailing faith for St. Peter and his successors referred to by Christ in Luke 22.
Luke 22:31-32- "And the Lord said: Simon, Simon, behold Satan hath desired to have all of you, that he may sift you as wheat: But I have prayed for thee, that thy faith fail not: and thou, being once converted, confirm thy brethren."
Satan desired to sift all the Apostles (plural) like wheat, but Jesus prayed for Simon Peter (singular), that his faith fail not. Jesus is saying that St. Peter and his successors (the popes of the Catholic Church) have an unfailing faith when authoritatively teaching a point of faith or morals to be held by the entire Church of Christ.
Pope Pius IX, Vatican Council I, 1870, ex cathedra: "SO, THIS GIFT OF TRUTH AND A NEVER FAILING FAITH WAS DIVINELY CONFERRED UPON PETER AND HIS SUCCESSORS IN THIS CHAIR…"Pope Pius IX, Vatican Council I, 1870, ex cathedra: "… the See of St. Peter always remains unimpaired by any error, according to the divine promise of our Lord the Savior made to the chief of His disciples: 'I have prayed for thee [Peter], that thy faith fail not ...'"
And this truth has been held since the earliest times in the Catholic Church.
Pope St. Gelasius I, epistle 42, or Decretal de recipiendis et non recipiendis libris, 495: "Accordingly, the see of Peter the Apostle of the Church of Rome is first, having neither spot, nor wrinkle, nor anything of this kind (Eph. 5:27)."
The word "infallible" actually means "cannot fail" or "unfailing." Therefore, the very term Papal Infallibility comes directly from Christ's promise to St. Peter (and his successors) in Luke 22, that Peter has an unfailing Faith. And it was also believed in the early Church, as we see here. Though this truth was believed since the beginning of the Church, it was specifically defined as a dogma at the First Vatican Council in 1870.
The Catholic Church teaches that those baptized persons who embrace heretical or schismatic sects will lose their souls. Jesus founded His Church upon St. Peter, and declared that whoever does not hear the Church be considered as the heathen and publican (Matthew 18:17). He also commanded His followers to observe "all things whatsoever" He has commanded (Matthew 28:20). The Eastern schismatic sects (such as the "Orthodox") and the Protestant sects are breakoff movements that have separated from the Catholic Church. By separating themselves from the one Church of Christ, they leave the path of salvation and enter the path of perdition.
These sects obstinately and pertinaciously reject one or more of the truths that Christ clearly instituted, such as the Papacy (Matthew 16; John 21; etc.), Confession (John 20:23), the Eucharist (John 6:54), and other dogmas of the Catholic Faith. In order to be saved one must assent to all the things which the Catholic Church, based on Scripture and Tradition, has infallibly defined as dogmas of the Faith.
Below are just a few of the infallible dogmas of the Catholic Faith which are rejected by Protestants and (in the case of the Papacy) by the Eastern "Orthodox." The Church "anathematizes" (a severe form of excommunication) all who obstinately assert the contrary to its dogmatic definitions.
"To understand the word anathema…we should first go back to the real meaning of herem of which it is the equivalent. Herem comes from the word haram, to cut off, to separate, to curse, and indicates that which is cursed and condemned to be cut off or exterminated, whether a person or a thing, and in consequence, that which man is forbidden to make use of. This is the sense of anathema in the following passage from Deut., vii, 26: 'Neither shalt thou bring anything of the idol into thy house, lest thou become an anathema like it. Thou shalt detest it as dung, and shalt utterly abhor it as uncleanness and filth, because it is an anathema.'" (The Catholic Encyclopedia Vol. 1, "Anathema" (1907))
Thus, a Protestant or an "Eastern Orthodox" who obstinately rejects these dogmatic teachings is anathematized and severed from the Church, outside of which there is no salvation. It's quite interesting that, in issuing these dogmatic canons, the Church says: "If anyone shall say…. let him be anathema [anathema sit]" as opposed to "If anyone shall say… he is anathema [anathema est]." This qualification of "let him be" allows room for those Catholics who may be unaware of a particular dogma and would conform to the teaching of the canon as soon as it were presented to him. The person who is obstinate, however, and willfully contradicts the dogmatic teaching of the Church receives the full force of the automatic condemnation.
The point here is that if one is able to reject these dogmas and still be saved, then these infallible definitions and their accompanying anathemas have no meaning, value or force. But they do have meaning, value and force – they are infallible teachings protected by Jesus Christ. Thus, all who reject these dogmas are anathematized and on the road to damnation.
Pope Pius XI, Rerum omnium perturbationem (#4), Jan. 26, 1923: "The saint was no less a person that Francis de Sales… he seemed to have been sent especially by God to contend against the heresies begotten by the [Protestant] Reformation. It is in these heresies that we discover the beginnings of that apostasy of mankind from the Church, the sad and disastrous effects of which are deplored, even to the present hour, by every fair mind."
Pope Julius III, Council of Trent, Session 13, Can. 1 on the Eucharist, ex cathedra:"If anyone denies that in the sacrament of the most holy Eucharist there are truly, really, and substantially contained the Body and Blood together with the soul and divinity of our Lord Jesus Christ, and therefore the whole Christ, but shall say that He is in it as by sign or figure, or force, let him be anathema."
Pope Julius III, Council of Trent, Session 14, Canon 3 on the Sacrament of Penance: "If anyone says that the words of the Lord Savior: 'Receive ye the Holy Ghost; whose sins you shall forgive, they are forgiven them; and whose sins ye shall retain, they are retained' [John 20:22 f.], are not to be understood of the power remitting and retaining sins in the sacrament of penance… let him be anathema."
Pope Julius III, Council of Trent, Session 14, on Extreme Unction and Penance: "These are the things which this sacred ecumenical synod professes and teaches concerning the sacraments of penance and extreme unction, and it sets them forth to be believed and held by all the faithful of Christ. Moreover, the following canons, it says, must be inviolately observed, and it condemns and anathematizes forever those who assert the contrary."
Pope Paul III, Council of Trent, Session 6, Chap. 16, ex cathedra:"After this Catholic doctrine of justification - which, unless he faithfully and firmly accepts, no one can be justified - it seemed good to the holy Synod to add these canons, so that all may know, not only what they must hold and follow, but also what they ought to shun and avoid."
Pope Pius IX, Vatican Council I, 1870, Sess. 4, Chap. 3, ex cathedra: "… all the faithful of Christ must believe that the Apostolic See and the Roman Pontiff hold primacy over the whole world, and the Pontiff of Rome himself is the successor of the blessed Peter, the chief of the apostles, and is the true vicar of Christ and head of the whole Church... Furthermore We teach and declare that the Roman Church, by the disposition of the Lord, holds the sovereignty of ordinary power over all others… This is the doctrine of Catholic truth from which no one can deviate and keep his faith and salvation."