The Church of the apostles was definitely one: “There is one body and one spirit,” Paul wrote, “just as you were called to the one hope that belongs to your call, one Lord, one faith, one baptism, one God and Father of us all” (Eph. 4:4-5). Paul linked this primitive unity to the Church’s common Eucharistic bread: “Because there is one bread, we who are many are one body, for we all partake of one bread” (1 Cor. 10:17). Jesus had promised at the outset that “there would be one flock, one shepherd” (John 10:16).
The Church of the apostles was holy. When we say that, we mean among other things that it had the all-holy God himself as author. We do not mean that all of its members have ceased to be sinners and have themselves become all-holy. On the contrary, the Church from the beginning, on her human side, has been composed of sinners: “Christ Jesus came into the world to save sinners” (1 Tim. 1:15). The Church was founded for no other reason than to continue Christ’s redemptive and sanctifying work with them in the world. Jesus founded his Church to continue his redemptive and sanctifying work in the world. Christians understand the holiness of the universal Church to derive from Christ’s holiness.
The Church from the beginning has been endowed with the sacramental means to help make holy the sinners who are found in her ranks. The Church has been given the sacraments along with the word precisely in order to be able to help make sinners holy.
The third mark of the true Church was that this Church was Catholic. “Catholic” means “universal.”The adjective “Catholic” means that in the church the wholeness of the Christian faith, full and complete, all-embracing, and with nothing lacking, is proclaimed to all people without excluding any part of the faith or any class or group of people.
It refers as much to the fullness of the faith which it possesses as it does to the undeniable extension in both time and space which has characterized it virtually from the beginning. At the very beginning, of course, it was no doubt difficult to see how the “little flock” (Luke 12:32) of which the Church then consisted could by any stretch of the imagination qualify as “universal.” Still, just as the embryo contains in germ the whole human being, so the Church already contained the universality that would quickly begin to manifest itself.
The Catholicity of the Church in resides in the fact that the Church is for everybody at all times as it does in the fact that it was indeed destined to spread everywhere throughout the whole world. Within a few years of the foundation of the Church, Paul was writing that “the word of truth . . . in the whole world . . . is bearing fruit and growing” (Col. 1:5-6).
Finally, the Church that issued from the commission of Christ to the apostles was necessarily apostolic. The Church’s origin and beliefs as rooted and continuing in the living Tradition of the Apostles of Jesus Christ founded the Church upon the apostles and in no other way: “Did I not choose you, the twelve?” he asked them (John 6:70). The apostles of all people understood perfectly well that they did not set themselves up in their own little community, as we sometimes today see “gospel churches” set up in store fronts or in the suburbs. The New Testament teaches, “One does not take the honor upon himself” (Heb. 5:4).