I will no longer be in the world, but they are in the world,
and I am coming to You. Holy Father, protect them by Your name,
the name You gave Me, so that they may be one as We are one.
John 17, 11

Since the time of the Apostles, the Church has viewed itself as the unblemished bride of Christ and has identified as Catholic. In this context, “Catholic” refers to a visible community of baptized Christians from diverse backgrounds around the globe who share the same faith. This community operates under the leadership of Christ, the invisible head. It is guided by the pope, his vicar, and the bishops worldwide who are in communion with the Roman Pontiff.

The early apostles recognized that Jesus Christ established His Church as a visibly unified and hierarchical entity to ensure the consistency of faith and the accurate transmission of the deposit of faith across generations. This guidance was believed to come under the influence of the Holy Spirit, as referenced in the Gospel of John (Jn 14:16; 16:12-13). A key example of this authority is how the apostles responded to Peter’s leadership during significant doctrinal discussions. When the question arose regarding whether baptized Gentiles should adhere to the Jewish practice of circumcision, none of the apostles challenged Peter’s authority to address the matter on behalf of the Church. Instead, they listened attentively to him and accepted his judgment as conclusive (as detailed in Acts 15). The council in Jerusalem may not have reached a widely accepted resolution if Peter’s role as the holder of universal authority had not been acknowledged. This recognition allowed the Church to receive a final decision with confidence and in unity (Mt 16:20).

The New Testament Church is described as catholic in a comprehensive religious sense. Several key passages in Scripture illustrate the Church’s self-understanding, derived from the knowledge imparted by the Holy Spirit and illuminated by the light of faith. For instance, in Matthew 5:14, Jesus mentions that a city, specifically Jerusalem, “set on a hill cannot be hidden.” This metaphor indicates that the Church, identified as the new Jerusalem descending from heaven, is inherently a visible entity comprising a unified community of believers, known as the Mystical Body of Christ.

Jesus emphasized the establishment of his “church” on Peter, referred to as the rock, alongside the apostles who are in communion with the Lord’s representative. He specifically mentioned the concept of a singular church without reference to multiple ‘churches’ (Mt 16:18). The unity of faith necessitates a visible organization guided by a visible leader, which in this context represents and remains accountable to the invisible leader, Christ. Without a visible head, a church cannot effectively function as a cohesive body. This leadership enables the church to exercise its authority through the principles of ‘binding and loosing,’ fostering a united faith community that reflects the true meaning of being catholic. In contrast, Protestantism tends to represent a fragmented religious movement characterized by numerous independent churches, each with its own governing bodies or leaders.

In the Gospel of John (10:16), Jesus speaks to the apostles about the necessity of having “one flock and one shepherd.” This phrase underlines the belief that there should be a singular, visible community of believers, led by a visible shepherd and an invisible shepherd, who is Christ in heaven. This structure highlights Jesus’ intention for his Church to be unified, as reflected in his prayer for his followers to be perfectly one, similar to his unity with the Father (John 17:11, 21, 23). The concept of perfect oneness is found within what is identified as the one true Church established by Christ, which is the Catholic Church. Despite historical challenges, such as heresies, divisions, and schisms caused by individuals deviating from Christ’s vision, the Catholic Church upholds this principle of unity.

The historical challenges faced by the Church, notably since the early fourth century with the rise of Arianism, can be seen as anticipated by Christ. In Matthew 12:30, Jesus stated, “He who is not with me is against me; and he who does not gather with me scatters,” emphasizing the importance of unity. For there to be perfect unity within the one, visible, and hierarchical Church, it is essential to heed the teachings of Peter and the apostles, along with their appointed successors in the episcopal office, until Christ’s return. Those who disregard or reject the authority of the Universal Magisterium not only turn away from the teachings of Christ but also ignore the authority passed down from the Father to Peter and the Apostles, as noted in Luke 10:16. This highlights the significance of adherence to the Church’s guiding authority for maintaining doctrinal unity.

The apostles and the faithful individuals they appointed to continue their roles within the episcopacy and priesthood (presbyterium) consistently upheld the vision of Christ in both their thoughts and actions. The New Testament church is characterized as the Catholic Church in both essence and spirit. In his letter to the believers in Rome, Paul encouraged them to maintain harmony among themselves (Rom 15:5). A unified body of believers, sharing one faith, cannot exist if dissenters create divisions that oppose the authoritative teachings established by the apostles.

It is essential to avoid false teachers and heed the warning found in Romans 16:17, which emphasizes the need for vigilance against those who challenge Church teachings. For the Church to maintain its universal nature, Christians must be cautious of individuals who introduce controversies by promoting their own incorrect ideas, thereby misleading the faithful with unclear and confusing messages, as noted in 1 Timothy 6:4. Historical examples such as the Judaizers and Ebionites illustrate this concern. A truly catholic Church requires a universal teaching authority that can trace its lineage and authority back to Christ. This principle was exemplified during the council in Jerusalem, where followers who dismissed the council’s decisions distanced themselves from communion with the true Church.

The concept of unity within Christianity is emphasized in the writings of Paul, who prays that Christians may be united in mind and spirit, reflecting the ideal of perfect harmony as articulated in 1 Corinthians 1:10. The Church is understood as the visible ‘body’ of Christ, distinct from His invisible spirit or soul, as noted in Ephesians 1:22-23 and Ephesians 5:23-32. According to this perspective, Christ has one bride—the Church—rather than multiple groups with varying interpretations of doctrine and morality, a sentiment echoed in Ephesian 5:25. Peter also encourages believers to pursue a unity of spirit, which is a fundamental principle of Catholicism, as stated in 1 Peter 3:8. However, achieving this unity can be challenging when individuals hold differing beliefs and disregard the central teaching authority of the Church due to personal opinions or feelings. This disconnect may lead to individuals distancing themselves from the Church community, potentially resulting in excommunication or schism. The notion that God is not the author of confusion but of peace and reconciliation, as referenced in 1 Corinthians 14:33, underscores the importance of unity in the faith.

The prophet Daniel predicted the establishment of the Catholic Church, which he recognized as divinely founded by Our Lord Jesus Christ. He envisioned a united community of believers from diverse nations dedicated to serving God’s kingdom on earth, as indicated in Daniel 7:14. Unlike a democracy characterized by various political or religious factions, the Church is understood to operate as a kingdom and monarchical institution, a concept supported by Revelation 7:9-10.

Bishop Ignatius of Antioch, who was martyred around A.D. 110, is regarded as a prominent early Christian figure and is believed to have been a follower or possibly a student of the apostle John. There are suggestions that John may have even ordained him. As one of the early apostolic successors, Ignatius stressed the significance of unity within the Church and highlighted its visible nature, referring to it as “one and catholic” in a biblical context. In his Epistle to the Smyrnaeans, Ignatius emphasizes the authority of the bishop, stating, “See that ye all follow the bishop, even as Christ Jesus does the Father… Let no man do anything connected with the Church without the bishop. Let that be deemed a proper Eucharist, which is administered either by the bishop or by one to whom he has entrusted it. Wherever the bishop shall appear, there let the multitude also be; even as, wherever Jesus Christ is, there is the Catholic Church” (Epistle to the Smyrnaeans, 8:2). This perspective underscores the integral role of bishops in maintaining the Church’s unity and the proper administration of its sacraments.

Ignatius’ teachings emphasize the importance of respecting the authority of bishops within Catholicism. He highlights that the validity of the Eucharist—a vital sacrament—is recognized only when it is administered by a bishop or an individual authorized by him, provided that they can trace their ordination back to the apostles through an unbroken line of succession. This foundational concept is supported by various scriptural references, including Acts 6:6, 9:17-19, 13:3, and 1 Timothy 4:14.

Irenaeus, who became the Bishop of Lyons (present-day France) around A.D. 180, played a significant role in the development of early Christian theology. He was a student of Polycarp, who is traditionally thought to have been taught by the apostle John. Irenaeus is known for his emphasis on the unity and goodness of God, a perspective that sharply contrasted with Gnostic beliefs. These beliefs often introduced a complex hierarchy of divine entities, including concepts such as the Monad and the Demiurge.

In the second century, a variety of Gnostic sects developed, each with unique interpretations of spirituality that emphasized personal spiritual experiences over established religious affiliations. While their beliefs varied widely, these groups shared a common goal of seeking secret knowledge, or gnosis, which they considered vital for their spiritual development. This pursuit of esoteric understanding positioned the Gnostic sects in direct conflict with the teachings of the nascent Catholic Church, which upheld the authority of Apostolic teachings concerning the nature of Christ in the incarnation.

In his critique of the Gnostics, particularly Marcion, Irenaeus underscores the significance of adhering to the teachings of the Church. He argues that those who abandon the Church’s preaching undermine the knowledge passed down from the “holy presbyters.” Irenaeus warns, “It behooves us, therefore, to avoid their doctrines, and to take careful heed lest we suffer any injury from them; but to flee to the Church, and be brought up in her bosom, and be nourished with the Lord’s Scriptures” (Against Heresies, 5:20). He characterizes Gnostic leaders as “teachers who are destitute of truly divine wisdom,” in stark contrast to the Catholic Church, which he asserts upholds a unified and consistent faith across the globe.

Irenaeus provided a comprehensive understanding of the term “catholic” in relation to the New Testament Church, highlighting its distinction from the superficial pluralism found within the Gnostic sects of his era. He argued that the teachings of the Church demonstrate a continuous and coherent lineage, supported by the testimonies of prophets, apostles, and early disciples. Irenaeus stated that the Church functions as the institution established by God, featuring pivotal roles such as apostles, prophets, and teachers, which serve as essential instruments for the work of the Spirit. Additionally, he stressed that individuals who separate themselves from the Church due to misguided beliefs or immoral actions risk depriving themselves of spiritual life.

According to Irenaeus, the relationship between the Church and the Spirit of God is foundational to understanding the nature of true Christianity. He articulated that where the Church exists, the Spirit of God is also present, and conversely, where the Spirit is found, there the Church and all forms of grace are as well. This underscores the view that the Church is not merely an abstract concept or spiritual entity but rather a tangible and organized institution characterized by a unified faith and a hierarchical structure. Irenaeus highlighted the essential role of the One Holy Spirit in ensuring the continuity and integrity of the faith through the important mechanism of Apostolic succession, reinforcing the idea that this lineage is vital for maintaining doctrinal truth.

In A.D. 254, Cyprian, Bishop of Carthage, provided significant insights into the early Church’s understanding of its identity as catholic. He underscored the critical relationship between the bishop and the Church, highlighting that “the bishop is in the Church, and the Church in the bishop.” This statement reflects the belief that any individual who separates themselves from the authority of the bishop is also separated from the Church. Cyprian critiques those who think they can establish a connection with God outside the Church’s leadership, emphasizing that the Church is fundamentally one and unified, strengthened by the relationships among its priests. This perspective can be found in his correspondence, specifically in To Florentius, Epistle 66/67.

The Alexandrian priest, Arius, introduced a different interpretation of Scripture that diverged from traditional teachings. He asserted that the Son did not coexist eternally with the Father and was not consubstantial with Him. To preserve its Catholic identity, the Church emphasized the importance of adhering to established dogmas and maintaining unity within the broader faithful community. Arius remained resolute in his beliefs, which found support among a notable number of bishops in the Eastern Church. This theological division led the Roman emperor to convene the First Ecumenical Council of Nicaea in A.D. 325. The council produced a decisive statement condemning those who claimed, “There was when He was not, and, before being born He was not, and that He came into existence out of nothing, or who assert that the Son of God is of a different hypostasis or substance…” The Catholic and apostolic Church officially anathematized these positions.

In the writings of Cyril, Bishop of Jerusalem, composed around A.D. 350, the concept of the Church as ‘catholic’ is explored by referencing the letters of Paul. He specifically cites a passage directed to Timothy, which states: “That thou mayest know how thou ought to behave thyself in the House of God, which is the Church of the Living God, the pillar and ground of the truth” (Catechetical Lectures, 18:25). This excerpt underscores the Church’s belief in one God and a singular divine truth, a conviction that is supported by the presence of the Spirit of truth within the community.

The vitality of the Church is fundamentally rooted in God’s life, which flows through its members and energizes its mission. The Holy Spirit plays a crucial role in this dynamic, ensuring that the bride of Christ—representative of the Church—remains unwavering in her faith even amidst challenges and trials. This divine presence is not merely abstract; it actively intercedes and guides the Church as it navigates the complexities of the modern world. Moreover, the Spirit assures the faithful of the authenticity and transmission of sacred truth, which must be embraced wholeheartedly and without hesitation. This transmission is rooted in the apostolic teaching authority established by Jesus Christ through His apostles, particularly Peter, who is considered the first pope. This teaching authority provides a solid foundation for doctrine and moral teaching, enabling the Church to uphold its teachings consistently throughout the ages.

As a result, this divinely ordained structure not only fosters unity among the faithful but also ensures that they form a cohesive body of believers, navigating their spiritual journey together. The Church, therefore, stands as a testament to the enduring legacy of apostolic authority, linking each generation of Christians back to the original teachings of Christ and His apostles, thereby preserving the integrity and unity of the faith.

“We are not to give heed to those who say, Behold here is Christ, but show him
not in the Church, which is filled with brightness from the East even unto the West;
which is filled with true light; is the ‘pillar and ground of truth’; in which, as a whole, is
the whole advent of the Son of Man, who saith to all men throughout the universe,
‘Behold, I am with you all the days of life even unto the consumption of the world.’”
Origen, Commentary on Matthew, Tract 30
(A.D. 244)

After this I looked, and behold, a great multitude which no man could number, from every
nation, from all tribes and peoples and tongues, standing before the throne and before the
Lamb, clothed in white robes, with palm branches in their hands, and crying out with a
loud voice, “Salvation belongs to our God who sits upon the throne, and to the Lamb!”
Revelation 7, 9-10