In these words Jesus promises that the Holy Ghost should so assist the apostles and their successors in their office as teachers that they should only proclaim the true doctrines of Christ. How can those be right who assert that the Church can err, and has already erred; for in that case the Spirit of truth would have departed from her, the promise of Christ would not be fulfilled, and His divinity would be at an end! Let him who can overthrow this argument!
4. In the third place, Jesus promised: "The gates (the power) of hell shall not prevail against it (the Church)." This power of hell, namely, the devil, would certainly overcome, i.e., prevail against the Church, if she would act in accordance with his will and desire. Before all else, however, he wills and desires that the Church should lose the true doctrines of Christ, whereby men are to be saved, and should teach what is false. As soon as he could succeed in bringing this about, he would prevail against the Church . But he can not conquer her, because of the promise of the Saviour; hence it follows that the Church can never err in matters of faith and morals; she must necessarily be infallible.
5. But as far as you, my dear young friend, are concerned, what follows from the fact of the Church's infallibility? This especially: make it your constant endeavor to become better acquainted with the true doctrine of the Catholic Church. How much mischief has resulted in the case of individuals, as well as in that of whole families, communities, and states, from the fact that they were in ignorance, either wilful or otherwise, of the true doctrine of the Church. Seek, therefore, a thorough explanation, a clear
