The True Church must be that which Jesus Christ personally founded, and the Apostles propagated. It must have existed continuously since the time of Christ. It must teach in their entirety all the doctrines commanded by the Divine Founder while He was still on earth; and all its members must profess those fundamental doctrines.
In spite of corruption and persecution, in spite of the combined forces of error and evil, the Catholic Church has continued to live and carry out its purpose, as its Founder promised through passing down the truths and the apostolic succession of bishops who, together, comprise the Magisterium of the Church. The indestructability of the Church, as has been proved by history, is alone enough to mark it as divine. God alone could have preserved it so long. The Church is the only institution which has proved itself an exception to the law of decay and death! It has watched the birth and decay of every government on earth for almost 2,000 years. After every attack against it, it rises, the Bride of Christ, ever fresh and fair through the unbroken apostolic line.
The chief marks of the Church are four. We have covered ONE, HOLY and CATHOLIC so far, today we cover APOSTOLIC.
Christ intended His Church to be propagated by His Apostles; and therefore the True Church must be Apostolic. It must be the Church propagated by the Apostles. Its rulers must derive their office and authority by the lawful succession from the Apostles. It must hold intact the doctrine and traditions of the Apostles, to whom Christ gave authority to teach.
It was Christ Himself, and no one else, Who chose His Apostles and disciples, and commanded them to teach His doctrines to all the world. To Simon Peter He said: "And I say to thee, thou art Peter, and upon this rock I will build My Church, and the gates of hell shall not prevail against it" (Matthew 16: 18).
Saint Paul says to the Galatians in Chapter 1, verse 8: "Even if we or an angel from Heaven should preach a Gospel to you other than that which we have preached to you, let him be anathema." The Apostle Paul also refers to the Church in Ephesians 2: 20 as "built upon the foundation of the Apostles."
Thus, we can prove that the only true Church of Christ is the Catholic Church, because: Only the Catholic Church possesses the marks of the Church established by Christ: that is unity, holiness, catholicity, and apostolicity. As a matter of fact, only the Catholic Church claims to have all these four marks of the True Church, the marks so evidently set by Christ.
Other than the Catholic Church, no other heretical Christian denomination is apostolic. The Protestant churches came some 1500 years later than the Church founded on the Rock of Peter. Their ministers cannot trace their succession from the Apostles. Not one teaches all the doctrines of the Apostles. How then could they be the Church founded by Christ? Truth and error are not the same and all other churches have errors in their doctrines because of the absence of all four marks. God is not divided. He revealed only one religion. We either believe that religion, or do not believe it. There is no middle way as Jesus says in Matthew 12: 30, "He who is not with Me is against Me." No one will assert that glass or zirconium is as valuable as diamonds nor that brass is as good as gold. No one claims that an imitation is just as good as the authentic thing. Why then would it be reasonable for a church to claim that a religion established by a man is as good as that founded by the Incarnate God?
From the very beginning of mankind there has been one true religion. From Adam to the coming of Christ this religion was preserved by the patriarchs, prophets and others chosen by God to keep the knowledge of the promised Redeemer intact. The Old Covenant was kept by the Jews, the "chosen people." All other nations had degenerated and worshipped idols and false gods. In spite of the imperfections of the old religion, it was always the true religion, the one true religion. It foreshadowed the coming of the perfect religion, that established by the Son of God, Jesus Christ, Who then abrogated the Jewish Faith, the Old Law, in favor of the New Faith, the New Law.
It would be absurd to suppose that God does not care whether men denounce His Son as an imposter and blasphemer. The Father does care if they worship His Son as God; He does care that His chosen people, as a whole, have rejected His Son, treating Jesus merely as a prophet. And Christ and His Apostles cared too. Why else would Christ, and after Him the Apostles and after them a long line of believers, have suffered so much and resisted persecution so firmly, if it were of no importance what a man believed? Saint Luke puts it in focus in Acts 4: 12, "There is no other name under Heaven given to men, whereby we must be saved."
The mark of Apostolicity is easily proved by the facts of history. If a church cannot trace back its history lawfully in an unbroken line step by step to the Apostles, it is not the True Church. The Catholic Church can. Pope John Paul II is the direct successor of St. Peter. He is the lawful successor of the Pope who preceded him; and thus each Pope lawfully succeeded the one before him, until we reach St. Peter, the first Pope, chosen by Christ Himself. All the Sees founded by the Apostles perished or were interrupted, except the See of Peter alone. Ubi Petrus, ibi Ecclesiam "Where Peter is, there is the Church" founded by the Son of God.
Those denominations that broke away from the Church thus lost their connection with the Apostles. They were all begun by individuals who could never have had any authority from either Christ or the Apostles. Non-Catholic denominations may claim that they did not begin new churches, but merely "reformed" the old one. But to that must be asked, Did the True Church exist at the time of the founding of these new churches or not? If it did not, then Christ's promise to be with His Church always had failed; His Church had died, and no human reform could possibly have resurrected it. That would also mean that Christ, Who is all-knowing, would have made a mistake. God doesn't make mistakes! Because of that the Church still exists. Therefore, those who invented new doctrines were not reforming it, but founding new churches, turning their backs on God's Will and, in effect, saying to God that they were more important than their Creator. They won't last long that way!
The Catholic Church derives all its holy orders, doctrines, and mission from the Apostles. It is "built on the foundation of the Apostles," of which Christ is the corner-stone (cf. Ephesians 2: 20). It holds intact the doctrine and traditions of the Apostles, to whom Christ gave authority to teach. A church which at any time denies an apostolic doctrine, discards the sacrament of Holy Orders, or breaks away from obedience to the Pope, ceases to be apostolic. It becomes a dead branch broken off from the parent vine which is Christ Himself: "I am the vine; you are the branches" (John 15: 5).