From:
https://sensusfidelium.us/apologetics/history-of-heresies-their-refutation-st-alphonsus/authors-preface/"1. My object in writing this work is to prove that the Roman Catholic Church is the only true one among so many other Churches, and to show how carefully the Almighty guarded her, and brought her victoriously through all the persecutions of her enemies. Hence, as St. Iræneus says (Lib. 3, cap. 3, n. 2), all should depend on the Roman Church as on their fountain and head. This is the Church founded by Jesus Christ, and propagated by the Apostles; and although in the commencement persecuted and contradicted by all, as the Jews said to St. Paul in Rome : ” For as concerning this sect (thus they called the Church), we know that it is gainsayed every where” (Acts, xxviii, 22); still she always remained firm, not like the other false Churches, which in the beginning numbered many followers, but perished in the end, as we shall see in the course of this history, when we speak of the Arians, Nestorians, Eutychians, and Pelagians; and if any sect still reckons many followers, as the Mahometans, Lutherans, or Calvinists, it is easy to see that they are upheld, not by the love of truth, but either by popular ignorance, or relaxation of morals. St. Augustine says that heresies are only embraced by those who had they persevered in the faith, would be lost by the irregularity of their lives (St. Aug. de Va. Rel. c. 8.)
2. Our Church, on the contrary, notwithstanding that she teaches her children a law opposed to the corrupt inclinations of human nature, not only never failed in the midst of persecutions, but even gained strength from them; as Tertullian (Apol. cap. ult.) says, the blood of martyrs is the seed of Christians, and the more we are mown down the more numerous we become; and in the 20th chapter of the same work he says, the kingdom of Christ and his reign is believed and he is worshipped by all nations. Pliny the Younger confirms this in his celebrated Letter to Trajan, in which he says that in Asia the temples of the gods were deserted, because the Christian Religion had overrun not only the cities but even the villages.
3. This, certainly, never could have taken place without the power of the Almighty, who intended to establish in the midst of idolatry, a new religion, to destroy all the superstitions of the false religion, and the ancient belief in a multitude of false gods adored by the Gentiles, by their ancestors, by the magistrates, and by the emperors themselves, who made use of all their power to protect it, and still the Christian faith was embraced by many nations who forsook a relaxed law for a hard and difficult one, forbidding them to pamper their sensual appetites. What but the power of God could accomplish this?
4. Great as the persecutions were which the Church suffered from idolatry, still greater were those she had to endure from the heretics which sprang from her own bosom, by means of wicked men, who, either through pride or ambition, or the desire of sensual license, endeavoured to rend the bowels of their parent. Heresy has been called a canker : ” It spreadeth like a canker” (II. Tim. ii, 17); for as a canker infects the whole body, so heresy infects the whole soul, the mind, the heart, the intellect, and the will. It is also called a plague, for it not only infects the person contaminated with it, but those who associate with him, and the fact is, that the spread of this plague in the world has injured the Church more than idolatry, and this good mother has suffered more from her own children than from her enemies. Still she has never perished in any of the tempests which the heretics raised against her; she appeared about to perish at one time through the heresy of Arius, when the faith of the Council of Nice, through the intrigues of the wicked Bishops, Valens and Ursacius, was condemned, and, as St. Jerome says, the world groaned at finding itself Arian (1); and the Eastern Church appeared in the same danger during the time of the heresies of Nestorius and Eutyches. But it is wonderful, and at the same time consoling, to read the end of all those heresies, and behold the bark of the Church, which appeared completely wrecked and sunk through the force of those persecutions, in a little while floating more gloriously and triumphantly than before.
4. St. Paul says: ” There must be heresies, that they also who are reproved may be made manifest among you” (I. Cor. ii, 19). St. Augustine, explaining this text, says that as fire is necessary to purify silver, and separate it from the dross, so heresies are necessary to prove the good Christians among the bad, and to separate the true from the false doctrine. The pride of the heretics makes them presume that they know the true faith, and that the Catholic Church is in error, but here is the mistake : our reason is not sufficient to tell us the true faith, since the truths of Divine Faith are above reason; we should, therefore, hold by that faith which God has revealed to his Church, and which the Church teaches, which is, as the Apostle says, ” the pillar and the ground of truth” (I. Tim. iii, 15). (1) St. Hieron. Dial, adversus Lucifer.
5. Hence, as St. Iræneus says, “It is necessary that all should depend on the Roman Church as their head and fountain; all Churches should agree with this Church on account of her priority of principality, for there the traditions delivered by the Apostles have always been preserved” (St. Iran, lib. 3, c. 3); and by the tradition derived from the Apostles which the Church founded at Rome preserves, and the Faith preserved by the succession of the Bishops, we confound those who through blindness or an evil conscience draw false conclusions (Ibid). ” Do you wish to know,” says St. Augustine, ” which is the true Church of Christ? Count those priests who, in a regular succession have succeeded St. Peter, who is the Rock, against which the gates of hell will not prevail” (St. Aug. in Ps. contra part Donat.) : and the holy Doctor alleges as one of the reasons which detain him in the Catholic Church, the succession of Bishops to the present time in the See of St. Peter” (Epis. fund, c. 4, n. 5); for in truth the uninterrupted succession from the Apostles and disciples is characteristic of the Catholic Church, and of no other.
6. It was the will of the Almighty that the Church in which the true faith was preserved should be one, that all the faithful might profess the one faith, but the devil, St. Cyprian says (2), invented heresies to destroy faith, and divide unity. The enemy has caused mankind to establish many different churches, so that each, following the faith of his own particular one, in opposition to that of others, the true faith might be confused, and as many false faiths formed as there are different churches, or rather different individuals. This is especially the case in England, where we see as many religions as families, and even families themselves divided in faith, each individual following his own. St. Cyprian, then, justly says that God has disposed that the true faith should be preserved in the Roman Church alone, so that there being but one Church there should be but one faith and one doctrine for all the faithful. St. Optatus Milevitanus, writing to Parmenianus, says, also : ” You cannot be ignorant that the Episcopal Chair of St. Peter was first placed in the city of Rome, in which one chair unity is observed by all” (St. Opt. I 2, cont. Parmen.) (2) St. Cyprian de Unitate Ecclesiæ.
7. The heretics, too, boast of the unity of their Churches, but St. Augustine says that it is unity against unity. ” What unity,” says the Saint, ” can all those churches have which are divided from the Catholic Church, which is the only true one; they are but as so many useless branches cut off from the Vine, the Catholic Church, which is always firmly rooted. This is the One Holy, True, and Catholic Church, opposing all heresies; it may be opposed, but cannot be conquered. All heresies come forth from it, like useless shoots cut off from the vine, but it still remains firmly rooted in charity, and the gates of hell shall not prevail against it” (St. Aug. lib. 1, de Symbol ad Cath. c. 6). St. Jerome says that the very fact of the heretics forming a church apart from the Roman Church, is a proof, of itself, that they are followers of error, and disciples of the devil, described by the Apostle, as ” giving heed to spirits of error and doctrines of devils” (I. Tim. iv, 1).
8. The Lutherans and Calvinists say, just as the Donatists did before them, that the Catholic Church preserved the true faith down to a certain period some say to the third, some to the fourth, some to the fifth century but that after that the true doctrine was corrupted, and the spouse of Christ became an adulteress. This supposition, however, refutes itself; for, granting that the Roman Catholic Church was the Church first founded by Christ, it could never fail, for our Saviour himself promised that the gates of hell never should prevail against it : “I say unto you that you are Peter, and on this Rock I will build my church, and the gates of hell shall not prevail against it” (Matt, xviii, 18). It being certain, then, that the Roman Catholic Church was the true one, as Gerard, one of the first ministers of Luther, admits (Gerard de Eccles. cap. 11, sec. 6) it to have been for the first five hundred years, and to have preserved the Apostolic doctrine during that period, it follows that it must always have remained so, for the spouse of Christ as St. Cyprian says, could never become an adulteress."
