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

The Roman Church is one both in symbolical confession and in social communion.

1. Symbolical confession. Everywhere on earth the Roman Church professes the same dogmas. This is evident above all from the same creeds recited publicly and privately by all; from doctrinal books, such as the catechisms of the individual churches, approved books of prayers, received scholastic-theological compendia, liturgical books; from sacred worship, by which with varied rites the same mysteries of the faith, the same sacrifice, the same sacraments are celebrated;¹ from the daily magisterium, by which bishops and priests preach the same faith throughout the whole world; finally from the submission of the faithful, who without any disputation obey the magisterium of the Church in all things that pertain to revealed truth.

Those, however, who pertinaciously resist the magisterium of the Church and publicly profess errors against the faith, by that very fact cease to be members of the Church. The Roman Church tolerates no heresy and no heretics in her bosom. Hence all Catholics assent with a wonderful harmony of faith. For although controversies are also carried on among them concerning theological matters, never however about defined dogmas. Although some Catholics understand the faith more perfectly, others less perfectly, nevertheless with one voice all, learned and unlearned, clerics and laity, confess the same doctrine revealed and proposed by the Church. "This faith", as St. Irenaeus already wrote, "the Church, and indeed disseminated throughout the whole world, diligently guards, as if inhabiting one house... as if having one soul and one heart, and consonantly preaches and teaches and hands on these things, as if possessing one mouth."²

2. Social communion. That the Roman Church is one in law and in fact is evident. By law, namely, or by the essential constitution of this Church, the faithful of the individual parishes are subject to their own local clergy; the local clergy together with the faithful are subject to the diocesan bishop; the diocesan bishops are subject to the Roman pontiff. The Roman pontiff is after the manner of a head, the bishops and their clerical helpers after the manner of joints, all the faithful after the manner of members of an organic body. And in fact it is indeed well known how intimate and continuous a communion obtains between the individual parts of this body. The Roman pontiff exercises the governance of the whole Church continuously; the bishops, joined to and subject to the pope, give continuous care to their individual churches both immediately and mediately through the local clergy; the faithful themselves render obedience to the hierarchical authority and above all to the Roman pontiff in religious matters. And although this obedience is not always perfect; although some sometimes resist the hierarchy (just as they also resist God himself), nevertheless as long as they wish to remain Catholics, they do not resist contumaciously. If, however, any are contumacious and rebellious, by that very fact they are no longer Catholics, but are cast out from the Church like branches cut off from the tree. In the Roman Church, therefore, schismatics neither are nor can be. Hence the Roman Church is truly one flock, one sheepfold, one family, one house, one kingdom, one mystical body of Christ. Indeed, the unity of this Church shines so much that it is an object of admiration to many adversaries, an object of mockery to many.