Just as the hypostasis of the Godman Christ is one and unique, so too is the Church, through Him, in Him and founded upon Him, one and unique.
Abba Justin Popovic, Publication: Orthodox Kypseli
The unity of the Church is necessarily the outcome of the unity of the Person of the Godman Christ. The Church, being an overall and a uniquely God-human organism in all the worlds, cannot possibly be divided. Every division would have spelled her death. Being wholly founded on the Godman, the Church is primarily a God-human organism and then a God-human organization. Because of this, whatever she has in her is God-human and indivisible: the faith, love, truth, baptism, Eucharist and every divine mystery and every divine virtue and generally all her life and structure. Therefore, also indivisible in her are her teaching and her works and her sanctification and theosis. Everything is by grace organically united, in one God-human body, of which Christ is the only and unique Head. All the members of the Church, namely the faithful – albeit as persons are integral and unjoined – when joined together by that one same grace of the Holy Spirit, through the sacraments and virtues into one organic unity, they comprise one body and one spirit and confess one faith (Eph.4:4-5), which unites them with Christ and with each other.
Along with the other apostles, the Christ-bearing Apostle of the Nations most of all preaches through the Holy Spirit the unity and uniqueness of her founding person, the Godman Christ: “For no other foundation can anyone lay next to the one that is laid, who is Jesus Christ” (1Cor 3:11).
Following the holy Apostles, the Fathers and Teachers of the Church, confess, preach and defend with the same zeal the unity and uniqueness of the Church of the Orthodox. Their zeal for the preservation of the unity of the Church was expressed mainly in the cases of people or groups of people who severed themselves from the Church, namely, in cases of heresies and schisms. On the topic of unity, a special significance and importance was and is ascribed to the Ecumenical and Local Synods of the Church. According to the uniform stance of the Fathers and the Synods, the Church is only one, but also unique, because the one and unique Godman, Her Head, cannot have many bodies. The Church is one and unique because it is the body of the one and only Christ. The dividing of the Church is ontologically impossible, which is why there has never been a division per se of the Church, but only a departure from the Church. According to the word of the Lord, the vine cannot be divided; only the voluntarily unfruitful vine branches fall off from the ever-living vine and dry up (John 15:1-6). At various times, heretics and schismatics had severed themselves from the one indivisible Church of Christ, who consequently ceased to be members of the Church and embodied in Her Godman body. Such were firstly the Gnostics, then the Arians and the Pneumatomachs (Spirit-opponents), then the Monophysites and Uniates and all the other heretic and schismatic legion.
“Saint Philotheos of Paros
The Ascetic and missionary apostle (1884-1980)”
Vol. 3 Sept-Dec 2001, Thessaloniki
Publication: Orthodox Kypseli.