Christ established His church upon a foundation as solid as a rock, and declared that the gates of hell, or forces of evil, would not prevail against it. This implies the perpetual retention of the truth taught by Christ, forbidding its corruption. He commanded her to teach all nations, “all things whatsoever I have commanded you; and behold I am with you all days even to the consummation of the world.” Matt. XXVIII., 20. His presence guarantees that she will ever teach a doctrine identical With His own principles. He promised that the Holy Spirit would abide with the Church forever, undoubtedly a pledge of perpetual infallibility. Jn. XIV., 16. St. Paul clearly manifests this doctrine by his words, “Behave thyself in the house of God, which is the Church of the living God, the pillar and ground of truth.” I. Tim. III., 15. The early Fathers insist upon the infallibility of the Church, and reason also tells us that the unity of the Church could not be maintained if she could fail in her teaching of the truth; her very holiness forbids heresy; her catholicity demands expansion without loss of the self-same teaching; whilst her apostolicity requires perpetual duration of an unchanged Apostolic doctrine. Finally, if the Catholic Church be not infallible, then there is no Church on earth which is such as Christ predicted.
Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty