Apologeticae sive Theologiae Fundamentalis, Tomus II (Pars Altera): Demonstratio Catholica

By the words of the apostle the Church is called "house of God"¹ or "temple of God"² by a singular name, besides which no other could be built, since it is built up out of all the faithful "upon the foundation of the apostles and prophets, Jesus Christ himself being the chief cornerstone."³ Likewise St. Paul calls the Church the bride of Christ⁴ and the (mystical) body of Christ.⁵ Christ, however, does not have many brides, nor many bodies. Indeed, the doctor of the Gentiles expressly intimates this as well by comparing all the faithful of Christ to one body, whose head is Christ.⁶

In the time of the apostles a single universal Church existed in fact. For the epistles of the apostles are either inscribed and sent to particular congregations, which nevertheless were joined with the other churches, or to all the faithful of the whole world. Likewise the council of the apostles gathered at Jerusalem about twenty years after the death of Christ binds all the faithful and prescribes the same laws to all.⁷ No trace, therefore, of a divided Church appears in the time of the apostles. From which we rightly conclude that Christ instituted only one Church.