He said to them, “But who do you say that I am?” Simon Peter said in reply, “You are the Messiah, the Son of the living God.” Jesus said to him in reply, “Blessed are you, Simon son of Jonah. For flesh and blood has not revealed this to you, but my heavenly Father. And so I say to you, you are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it. I will give you the keys to the kingdom of heaven. Whatever you bind on earth shall be bound in heaven; and whatever you loose on earth shall be loosed in heaven.”
Matthew 16, 16-19

Papal infallibility is a significant doctrine in Roman Catholic theology, asserting that the pope, when acting as the supreme leader of the Church and under extraordinary circumstances, is incapable of error in his teachings on matters of faith and morals. This doctrine is rooted in the belief that Jesus entrusted the Church with a mission to teach, which must adhere faithfully to His teachings. The Holy Spirit plays a crucial role in this process, ensuring that the Church's teachings are always absolutely true and can be accepted without any doubt.

The charism of papal infallibility guarantees that the teachings of the Church reflect those of Christ without any distortion. It's important to note that while papal infallibility is related to the Church's enduring nature, or indefectibility, the two concepts are distinct. Indefectibility refers to the assurance that the grace promised by Jesus will preserve the Church's faith until the end of time, as it awaits the glorious return of the Lord.

The definition of the First Vatican Council (1869-70) states the conditions under which the pope has spoken infallibly or ex-cathedra (“from his chair” of supreme teacher): 1. “The Roman pontiff speaks;” 2. “he speaks ex-cathedra;” 3. “defines the following;” 4. “that doctrine concerning faith and morals;” 5. “must be held by the whole Church.” We have one instance of a pope speaking ex-cathedra with infallibility in the Apostolic Constitution, Benedictus Deus, of Pope Benedict Xll in A.D. 1336.

1 (The Roman Pontiff speaks)
“The Apostolic Constitution, Benedictus Deus, of Pope Benedict Xll”

2 (Speaks ex-cathedra)
“with apostolic authority”

3 (We pronounce, declare, and define)
“define the following”

4 (That doctrine concerning faith and morals)
Pope Benedict declares ex-cathedra that each soul will be particularly judged immediately after death
according to his or her deeds before the general day of judgment.

5 (Must be held by the whole church)
“which is to remain in force forever”

Papal infallibility is defined as a dogma of the Catholic Church, established by the First Vatican Council. This doctrine asserts that, in accordance with Jesus’ promise to Peter, the Pope is safeguarded by the Holy Spirit from making doctrinal errors when he exercises his universal primacy of authority, particularly in his Extraordinary Magisterium. This means that when the Pope teaches on matters of faith and morals, he is protected from error, ensuring that the teachings align with the original doctrine given to the apostolic church and preserved within the deposit of faith, which includes both Scripture and Tradition.

The pope isn’t only the visible head of the Church but also the head of the episcopal college. When Jesus founded the Twelve, “he constituted them in the form of a college or permanent assembly, at the head of which he placed Peter, chosen from among them.” Just as Peter and the Apostles constitute a single apostolic college, likewise the Roman Pontiff (Peter’s apostolic successor) and the bishops in the entire world (successors of the rest of the apostles) are associated with each other in a bond of unity (Catechism of the Catholic Church, 880).

Jesus made Simon, whom he would name Peter, the “rock” of his Church. He gave Peter the “keys” of his Church and established him as shepherd of the entire flock. The office of “binding and loosing” was given to Peter and assigned to the College of Apostles, united to its head (CCC, 881). Bishop Vincent Ferrier Gassier explains the importance of this prerogative that our Lord conferred on Peter. “The purpose of this prerogative is to preserve truth in the Church. The special exercise of this prerogative occurs when there arise somewhere in the Church scandals against the faith, i.e., dissensions and heresies that the bishops of the individual churches or even gathered together in the provincial council are unable to repress so that they are forced to appeal to the Apostolic See (in Rome) regarding the case, or even the bishops themselves are infected by the sad strain of error” (The Gift of Infallibility: Ignatius Press, 2008). This pastoral office of Peter and the other apostles belongs to the Church’s foundation. It is continued by the bishops united to the Pope under his universal primacy of authority.

The bishop of Rome, known as the pope, serves as Peter’s successor in a universal capacity. He acts as the “perpetual and visible source and foundation of the unity both of the bishops and of the whole company of the faithful” (CCC, 882). As the Vicar of Christ and the pastor of the entire Church, the Roman Pontiff possesses “full, supreme, and universal power over the whole Church, a power which he can always exercise unhindered” (CCC, 883).

The College of Bishops, however, does not hold the authority to teach infallibly unless it is united with the Pope, who is the head of the entire Church, encompassing both clergy and laity. While the College of Bishops has “supreme and full authority over the universal Church,” this power cannot be exercised independently of the Roman Pontiff. The College formally exercises its authority in an ecumenical council, but it is important to note that “there never is an ecumenical council which is not confirmed or at least recognized as such by Peter’s successor” (CCC, 884). During an ecumenical council, when the College of Bishops defines matters of faith and morals in unity with the pope, this collective action is referred to as the Universal Magisterium.

Since the Roman Pontiff is believed to be graced with the charism of infallibility in virtue of being the apostolic successor of Peter, we must turn to the New Testament to see whether Jesus had, in fact, established the apostle as the visible head of the Church and bestowed on him the gift of infallibility. To make this determination, we must examine the meaning of the words “rock” and “keys” and the power to “bind and loose” while, in the meantime, uncovering the ancient Jewish roots of Peter’s unique office that lends it credibility and establishes its validity.

Scriptural support for the pre-eminence of Peter in the nascent church and his unique role as head shepherd is found in the fact that his name is mentioned no less than 191 times in the New Testament. Next in line is the beloved disciple John, who is mentioned 48 times. However, if this isn’t strong enough evidence, we can turn to the list of the apostles in the Gospel of Matthew to support the Church’s tradition. We read in Chapter 2, Verse 1: “The names of the twelve apostles are these: First, Simon called Peter,” The Greek word for “First” that describes Peter is protos (πρῶτος). Methodist theologian and professor James H. Strong defines the word “before, principal, most important” (Strong’s Exhaustive Concordance of the Bible: Hendrickson, 2009. Entry 4413. Protos).

In other words, among the apostles, Peter is “first and foremost” or “primary first.” Peter’s description as being “first” is not “an arbitrary numerical detail” or a “chronological indicator” of when Peter became an apostle. We see in John 1:41 that Peter’s brother Andrew was the first one Jesus chose to be an apostle of his. Peter’s name appears first in the list of apostles because he is the “primary” apostle within the entire college (John Salza, The Biblical Basis for the Papacy: Our Sunday Visitor Publishing Division, 2007).

Other New Testament writers use protos to describe the pre-eminence of individuals. Luke uses protos to describe Publius as “the chief (protos) man on the island” (Acts 28:7). He was the chief magistrate of the island of Melita and a man of authority. Paul also describes himself as a sinner “of whom I am the chief (protos). Other translations have Paul humbly describe himself as the “foremost” sinner (1 Tim 1:15). In the Septuagint (Old Testament), protos is also used as a title of pre-eminence. The sacred author describes the “chief (protos) singers appointed, to praise with canticles, and give thanks to God” (2 Ezdra 12:45; 2 Neh in the RSV-CE). So, Peter is described as “the first” of the apostles because he is the “chief” or “foremost” among them. He holds a pre-eminent place in the apostolic college (The Biblical Basis for the Papacy).

The relationship between Jesus and Peter during Jesus' three-year public ministry highlights Peter's significant role among the apostles. Notably, Peter is the first apostle to acknowledge Christ's divinity. In Matthew 16:16-17, Jesus tells Peter that this profound understanding comes from a special revelation by God the Father. This moment is pivotal, as it establishes Peter as the foundation upon which Jesus builds His Church, with the other apostles serving as essential supports and Jesus Himself as the cornerstone (Mt 16:18).

Moreover, the keys of authority over the Church—a symbol of governance over both clergy and laity—are entrusted uniquely to Peter (Mt 16:19). An illustrative incident occurs when a tax collector approaches Peter regarding the payment of the temple tax for Jesus. This scenario emphasizes Peter's recognized role as Jesus' spokesperson (Mt 17:24-25). This concept aligns with the Catholic understanding of the pope as the vicar of Christ, who speaks on behalf of Jesus, especially in ex-cathedra declarations. Furthermore, in Matthew 17:26-27, Jesus instructs Peter to find a coin in a fish's mouth to pay both His and Peter's tax, underscoring Peter's function as Jesus' representative on earth.

In various biblical accounts, Peter often assumes a leadership role among the apostles. For instance, in Matthew 18:21, he asks Jesus to clarify the rules regarding forgiveness, demonstrating his willingness to seek understanding on behalf of the group. Additionally, in Matthew 19:27 and Mark 10:28, Peter speaks for all the apostles when he acknowledges their decision to leave everything behind to follow Jesus. During critical moments, such as in the Garden of Gethsemane at the beginning of Jesus' passion, Peter's leadership is highlighted further. While Jesus prays, Peter and the other apostles are found asleep; however, it is Peter whom Jesus directly questions about his inability to stay awake (Mk 14:37). This interaction underscores Peter's special accountability as a leader among the apostles, as he is expected to be vigilant and set a proper example for the others during such pivotal times.

In the Gospel of Luke, an interesting moment occurs when Jesus chooses to preach from Peter’s boat (Lk 5:3). In biblical typology, a boat often symbolizes the Church, much like Noah’s Ark in the Old Testament. This specific instance suggests that Jesus provides guidance to His Church through His appointed leader, Peter. It is noteworthy that Jesus instructs Peter, the foremost among the apostles, to cast his net once more into the water, which leads to a miraculous catch of fish (Lk 5:4, 10). This event underscores Peter's role as the chief "fisher of men." The significant catch highlights that without Jesus, Peter would not have been able to achieve such extraordinary results, especially considering the timing when fish were typically not active. Consequently, Peter’s authority is rooted in Jesus, who is the Head of the Church, and the effectiveness of Peter's leadership is dependent on the grace provided by Jesus.

In the Gospel, Peter frequently assumes the role of spokesperson for the apostles, particularly evident in moments such as when Jesus asks who touched his garment (Lk 8:45). This pattern suggests that the other apostles may have viewed Peter as their leader, leading them to refrain from speaking first out of respect or a sense of hierarchy. Peter not only takes the initiative to respond but also represents the collective voice of the apostles. This is further illustrated during the Transfiguration, where he is the first apostle to ascend the mountain (Lk 9:28, 33) and when he seeks clarification regarding a parable (Lk 12:41).

In the Gospel of Luke (22:31-32), Jesus specifically prays for Peter, emphasizing the importance of his faith and instructing him to strengthen the other apostles in their moments of doubt. Peter's role as a leader in the apostolic community is crucial; his faith must remain strong to maintain the unity and integrity of the group. This highlights the greater responsibility that Peter holds in ensuring that the other apostles remain steadfast in their beliefs and in communion with him. Furthermore, the grace that Jesus grants Peter is intended to protect him from conveying false teachings. This same grace is also available to the other apostles, but it is contingent upon Peter's engagement and collaboration in their ministry.

In the Gospel of John, during the Last Supper, Jesus takes the significant step of washing Peter’s feet, exemplifying the role of a servant leader (Jn 13:6-9). While Peter might have chosen to wash the feet of the other apostles in imitation of Jesus, this action is not recorded in Scripture. Notably, Jesus questions Peter in front of the other apostles, asking if he loves Him more than they do (Jn 21:15), highlighting Peter's designated role as the visible head of the apostolic Church. Peter's primary allegiance is to Christ, reflecting a commitment without compromise. Before Jesus ascends to the Father, He tasks Peter with the responsibility to “feed [his] lambs” and “feed [his] sheep” (Jn 21:15-17), indicating that these lambs and sheep represent all people, including the apostles themselves. Thus, Peter, as the first pope, is entrusted with the vital duty of nurturing the faith among both clergy and laity on a universal scale.

Peter holds a distinctive role as "the first" of the apostles, which is highlighted in Matthew 16:13-19. In this passage, Simon Peter demonstrates a remarkable ability to receive and articulate divine knowledge from God, a key aspect of Christological understanding. This ability reflects what the Catholic Church defines as papal infallibility. It is important to note that the pope is not inherently infallible; instead, this infallibility is believed to operate through the guidance of the Holy Spirit, assisting in the accuracy of his thoughts. When Simon makes his first papal infallible decree, he is named Peter, derived from the Greek word "Petros." This renaming is significant since 'Cephas' (or Kepha) serves as a Greek transliteration of the Aramaic term for "rock," further emphasized in several biblical references, including John 1:42 and 1 Corinthians 1:12.

The Greek text is a translation of Jesus’ words, which were actually spoken in Aramaic. Aramaic only had one word for rock, kepha which explains why Peter is often called Cephas in the Bible. The word kepha in Aramaic means “huge rock.” The Aramaic word for “little stone” is evna and Peter isn’t called “Evna.” In Aramaic, Jesus said, “You are Peter (Kepha), and upon this rock (kepha) I will build my Church.” The metaphor works well in Aramaic, where nouns are neither feminine nor masculine.

D. A. Carson explains, “… the words petros and petra were synonyms in first-century Greek. They meant “small stone” and “large rock” in some ancient Greek poetry, centuries before the time of Christ, but that distinction had disappeared from the language by the time Matthew’s Gospel was rendered in Greek. The difference in meaning can only be found in Attic Greek, but the New Testament was written in Koine Greek—an entirely different dialect. In Koine Greek, both petros and petra simply meant “rock.” If Jesus had wanted to call Simon a small stone, the Greek lithos would have been used” ( The Expositor’s Bible Commentary [Grand Rapids: Zondervan, 1984], Frank E. Gaebelein, ed., 8:368).

In the kingdom of David, kings delegated their authority to a chief steward, who governed in the king's absence. This delegation of power was formally recognized through the presentation of the keys to the kingdom, symbolizing the steward's role as the "keeper of the keys." The chief steward, also known as a vizier or vicar, held a position of great authority, second only to the king, overseeing the palace and having the power to pass judgment on the king’s subjects. In his mission to restore the kingdom of David, Jesus similarly appointed a chief steward, granting him the keys to what would become the visible kingdom on Earth—the Church. He designated Peter as the leader over "the house of God," as referenced in biblical passages such as 2 Corinthians 5:1, 1 Timothy 3:15, and 1 Peter 4:15. This appointment empowered Peter to rule and govern God’s household following Jesus’ ascension into heaven, reflecting the governance structure established in the kingdom of David.

The Hebrew Scriptures mention “keys” only once, in the context of the authority of the Davidic king’s chief steward. Around 715 B.C., Hezekiah was the king of the Southern Kingdom, and Shebna was his chief steward or vicar. Through the prophet Isaiah, God reveals that He will remove Shebna from his office and replace him with Eliakim, to whom he will give the “key to the house of David.”

This is what the Lord, the Lord Almighty, says:
Go, say to this steward,
to Shebna the palace administrator:
What are you doing here and who gave you permission
to cut out a grave for yourself here,
hewing your grave on the height
and chiseling your resting place in the rock?
“Beware, the Lord is about to take firm hold of you
and hurl you away, you mighty man.
He will roll you up tightly like a ball
and throw you into a large country.
There you will die
and there the chariots you were so proud of
will become a disgrace to your master’s house.
I will depose you from your office,

“In that day I will summon my servant, Eliakim son of Hilkiah. I will clothe him with your robe and fasten your sash around him and hand your authority over to him. He will be a father to those who live in Jerusalem and to the people of Judah. I will place on his shoulder the key to the house of David; what he opens no one can shut, and what he shuts no one can open. I will drive him like a peg into a firm place; he will become a seat of honor for the house of his father.
Isaiah 22, 15-23

In the biblical narrative, God bestows upon Eliakim the key to the house of David, a position that was previously held by Shebna. This role is characterized by its transferability, allowing for the appointment of successors. By possessing the key to David's kingdom, Eliakim is granted the authority to make decisions that cannot be undone; what he opens remains open, and what he closes remains closed. This denotes that his judgments are final and serve as a representation of the king's will in the king's absence. Eliakim is described as a "father" to Israel, signifying his important role in guiding and overseeing the nation. This scenario reflects the belief that just as God actively governed in the Old Dispensation, He continues to oversee the administration of His kingdom in the New Dispensation.

The selection of King Hezekiah's reign by God as the time to disclose the lineage of the chief steward holds considerable significance. This is illustrated in the scripture found in Isaiah 7:14.

Therefore, the Lord Himself will give you a sign:
Behold, the virgin shall conceive and bear a Son,
and shall call His name Immanuel.
Isaiah 7, 14

The "great sign" described in the book of Revelation (Rev 12:1-5) symbolizes the restoration of the Davidic Messianic kingdom, represented by the Blessed Virgin Mary giving birth to the Messiah King. This event, known as the Nativity of Christ, fulfills numerous Old Testament prophecies regarding restoration, as noted in Micah 5:1-3. In ancient Judaic tradition, King Hezekiah is viewed as a significant prefiguration of the Messiah, more so than other kings from the Davidic line. In a Christian context, Hezekiah’s story bears a closer resemblance to that of Christ. Specifically, God decrees that Hezekiah will become gravely ill, but He also promises to raise him up or heal him on the third day, reflecting a key theme of resurrection and divine intervention.

In those days Hezekiah became ill and was at the point of death. The prophet Isaiah son of Amoz went to him and said, “This is what the Lord says: Put your house in order, because you are going to die; you will not recover.” Hezekiah turned his face to the wall and prayed to the Lord, “Remember, Lord, how I have walked before you faithfully and with wholehearted devotion and have done what is good in your eyes.” And Hezekiah wept bitterly. Before Isaiah had left the middle court, the word of the Lord came to him: “Go back and tell Hezekiah, the ruler of my people, ‘This is what the Lord, the God of your father David, says: I have heard your prayer and seen your tears; I will heal you. On the third day from now you will go up to the temple of the Lord.
2 Kings 20, 1-5

The resurrection of Hezekiah on the third day positions him as a significant Messianic figure among the kings who succeeded David. His role serves as a precursor to the Messiah, and his kingdom symbolizes the anticipated kingdom of our Lord and King within the lineage of David. Hezekiah had a series of chief stewards, which parallels the succession of chief stewards that Jesus would have. For example, Linus became the first successor to Peter around A.D. 67, as indicated in 2 Timothy 4:1. Additionally, Eliakim was recognized as a “father” to Israel in the kingdom of Judah, similar to how Peter and his successors are regarded as “holy fathers” in the new kingdom or house of Israel, which we understand as the Church. This establishes a biblical foundation for appointing Peter as the steward or vicar of Jesus’ kingdom on Earth. Within this context, we can now explore the subject of 'binding and loosing.'

The authority to "bind and loose" is an important concept in a biblical context, paralleling Eliakim's power to "open and shut." This authority is specifically conferred upon Peter by Jesus, distinguishing him from the other Twelve Apostles. In Jewish tradition, the terms "binding and loosing" (Hebrew: asar ve-hittar) were commonly used by religious authorities to describe their legislative and judicial roles. According to John Salza, these terms referred to the ability to "forbid" or "permit," encompassing rules of conduct (halakah) for the community and providing authoritative interpretations of Scripture, oral tradition, and the entirety of the Mosaic law. Essentially, this language captured the Pharisees' jurisdiction over doctrinal and disciplinary issues (The Biblical Basis for the Papacy).

In Acts 15:12-17, Peter demonstrates his authoritative role during the general council held in Jerusalem, where a significant doctrinal and disciplinary debate arose concerning the necessity of circumcising Gentile converts after their baptism. During this council, none of the attending apostles challenge or dispute Peter's stance; they remain silent as he addresses the issue. Following Peter's decisive statement—made in his capacity as Christ's chief steward or representative on Earth—both Paul and Barnabas, who are also bishops, offer their support for Peter's declaration. Additionally, James, the Bishop of Jerusalem, who presides over the council, agrees with Peter's resolution.

In the time of Jesus, the scribes and Pharisees served as the successors to Moses and were recognized as the appointed religious teachers of Israel. The term “chair of Moses,” mentioned by Jesus in Matthew 23:2-4, represents their authority to interpret and explain the Mosaic law. This chair was typically positioned in the center of a synagogue, where the official teacher of the Law would sit to read the Scriptures and communicate with the congregation. This custom is rooted in Exodus 18, where it is noted that “the next day, Moses sat to judge the people” (v. 13). From this chair, Moses delivered God’s judgments. He explained, “The people come to me to seek the judgment of God. And when any controversy arises among them, they come to me to judge between them, and to show the precepts of God and His laws” (vv. 15-16). The authority and tradition associated with Moses’s chair were passed down through generations to various leaders, including Joshua, the judges or elders, the prophets, and ultimately to the Sanhedrin during Jesus’ era. The chair symbolizes a divine office, indicating that there should be recognized successors in this role (The Biblical Basis for the Papacy).

Jesus himself acknowledged the scribes and Pharisees as legitimate successors to the chair of Moses and taught them with his authority, despite their personal shortcomings and imperfections. Our Lord told the apostles to observe “everything” (panta hosa) they said while sitting on the chair (Mt 23:5-7). And although Jesus harshly criticized them for abusing their divine authority and exercising it in pride and contempt towards the common Jew, notably the marginalized (Mt 23:5-7, 13), he acknowledged their authority to “bind” and “loose” and to “open” or “shut” in the kingdom of God in matters of faith and morals following the Torah.

In the context of his teachings, Jesus employs terminology that resonates with the Jewish audience, signaling the establishment of a new authority structure within his Church. This shift represents a transfer of both power and teaching authority from the Jewish teachers of the Law to the followers of Christ's teachings, as indicated in Galatians 6:2. The New Covenant, which is rooted in grace and charity (agape), supersedes the Old Covenant's Law, which included numerous civil and ceremonial regulations. This transition signifies a replacement of Moses's chair with that of Peter. Similar to Moses, Peter is granted the authority to pronounce divine judgments, as referenced in Exodus 18:15, and he is designated as the official interpreter of God’s Word, as discussed in 2 Peter 3:16.

Furthermore, Peter is bestowed with the power akin to that of Eliakim, who had the ability to “open” what none could “shut” (Isa 22:22). Reflecting the authority of the Sanhedrin of his era, Peter is also empowered to “shut the kingdom of heaven” against those who reject his teachings (Mt 23:13). Importantly, it is only Peter and his successors in the papacy who possess the full authority to excommunicate individuals deemed heretics or schismatics, regardless of whether they hold clerical or lay positions within the Church.

The concept of papal infallibility and the universal primacy of papal authority is supported by biblical texts and ancient traditions within the Church established by Christ. According to scripture, what Peter binds on earth is bound in heaven, and what he looses on earth is loosed in heaven. This notion of binding (estai dedemenon) and loosing (estai lelumenon) is expressed in the passive voice, which can be understood as “shall be bound” or “shall have been bound” (The Biblical Basis for the Papacy). This indicates that heaven ratifies Peter's decisions to bind and loose. Additionally, it is believed that the Holy Spirit guides Peter in making these decisions in accordance with divine revelation. Just as God revealed essential truths regarding salvation to Peter, it is asserted that God will confirm all of Peter's official teachings on salvation, extending this assurance to all his successors in the papal office.

The use of the future tense in the phrase “shall be bound” indicates that the ratification by heaven of Peter’s decisions will take place at the moment he makes them. This ratification is guided by the Holy Spirit, ensuring that Peter's pronouncements are not the result of personal judgment or arbitrary theological opinions. The unique application of the future tense in the passive voice emphasizes that Peter speaks on behalf of heaven, much like when he acknowledged the divinity of Christ. Therefore, the decisions regarding binding and loosing made by Peter are divinely ordained (The Biblical Basis for the Papacy).

Papal infallibility refers to the belief that God protects the Pope, specifically when he speaks ex cathedra, or "from the chair," ensuring that he does not teach error concerning matters of faith and morals. This doctrine holds that the Holy Spirit guarantees the truth of what the Pope declares, as part of divine revelation. According to the teachings of the Church, Jesus promised that the gates of hell would not prevail against it and that the Holy Spirit would guide the Church in all truth (John 16:12-13; cf. 1 Timothy 3:15) until his return. As such, teachings delivered ex cathedra are viewed as definitive and infallible, meant to be accepted by the entire Church without doubt, as they are believed to carry the seal of the Holy Spirit.

Early Sacred Tradition

St. (Pope) Clement of Rome (A.D. 98)
1st Epistle to the Corinthians, 1,59:1

“The church of God which sojourns at Rome to the church of God which sojourns at Corinth
… But if any disobey the words spoken by him through us, let them know that they will involve
themselves in transgression and in no small danger.”

St. Cyprian of Carthage (A.D. 251)
The Unity of the Church, 4-5

“And he says to him again after the resurrection, ‘Feed my sheep.’ It is on him that he builds the Church, and to him that he entrusts the sheep to feed. And although he assigns a like power to all the apostles, yet he founded a single Chair, thus establishing by his own authority the source and hallmark of the (Church’s) oneness. No doubt the others were all that Peter was, but a primacy is given to Peter, and it is (thus) made clear that there is but one flock which is to be fed by all the apostles in common accord. If a man does not hold fast to this oneness of Peter, does he imagine that he still holds the faith? If he deserts the Chair of Peter upon whom the Church was built, has he still confidence that he is in the Church? This unity firmly should we hold and maintain, especially we bishops, presiding in the Church, in order that we may approve the episcopate itself to be the one and undivided.”

Council of Sardica, To Pope Julius (A.D. 342)

”The reason for your absence was both honorable and imperative, that the schismatic wolves might not rob and plunder by stealth nor the heretical dogs bark madly in the rapid fury nor the very serpent, the devil, discharge his blasphemous venom. So it seems to us right and altogether fitting that priests of the Lord from each and every province should report to their head, that is, to the See of Peter, the Apostle.”

St. Optatus of Mileve (A.D. 367
The Schism of Donatists, 2:2-3

“You cannot deny that you know that in the city of Rome the Chair was first conferred on Peter, in which the prince of all the Apostles, Peter, sat…in which Chair unity should be preserved by all, so that he should now be a schismatic and a sinner who should set up another Chair against that unique one.”

Council of Ephesus, Session III (A.D. 431)

“Philip, presbyter and legate of the Apostolic See, said: There is no doubt, and in fact it has been known in all ages, that the holy and most blessed Peter, prince and head of the apostles, pillar of the faith, and foundation of the Catholic Church, received the keys of the kingdom from our Lord Jesus Christ, the Saviour and Redeemer of the human race, and that to him was given the power of loosing and binding sins: Our holy and most blessed Pope Celestine the bishop is according to due order his successor and holds his place…Accordingly the decision of all churches is firm, for the priests of the eastern and western churches are present…Wherefore Nestorius knows that he is alienated from the communion of the priests of the Catholic Church.”

Council of Chalcedon, Session III (A.D. 451)

“Wherefore the most holy and blessed Leo, archbishop of the great and elder Rome, through us, and through this present most holy synod together with the thrice blessed and all-glorious Peter the Apostle, who is the rock and foundation of the Catholic Church, and the foundation of the orthodox faith, hath stripped him of the episcopate, and hath alienated from him all hieratic worthiness. Therefore let this most holy and great synod sentence the before mentioned Dioscorus to the canonical penalties.”

But I have prayed for thee, that thy faith fail not:
and thou, being once converted, confirm thy brethren.
Luke 22, 32