The Church that Christ came to found was to teach truth. For that precise object was it established, and by that ultimate end, it is clear, all her institutions are to be justified or repudiated. Her infallibility, her indefectibility, her holiness, her Catholicism are defended by that simple and primary fact. To it also can we trace that note of apostolicity which, since the fifth century, it has become traditional to demand for the true Church of Christ. For consider what she has to do to justify her claim to be the true Church of Christ. Not only has she to prove that all that He taught she also teaches, or that she can make good her boast that there is none other than she that so closely clings to the doctrines that He set out to preach clings to them in spite of every age-long endeavour to assert their incompatibility with contemporary movements (for she has felt that to be up-to-date is little required by that which is not of time but of eternity); but over and above this she has also to prove that she bears His commission. That is to say, it is not enough to show that you hold the doctrines taught by our Lord, but it is also necessary to show that you have His permission to represent Him. There must be some sort of official recognition, otherwise we might be entertaining false Christs and false prophets; consequently we have a right to demand from the Church that she should show her connection with the apostolic band to whom Christ gave the sacred commission to preach His Gospel to every living creature. We have a right to ask her to show how she has descended from that first generation that was of God and taught by God Himself. She must, in other words, trace her line back to the Apostles.
Now this must not be taken to mean that she has to prove historically that each link in the chain is intact; not, indeed, because this cannot be done, but because we have not the time, the learning, or the opportunity for accurately testing this documentary evidence. Already in the fifth century, Saint Augustine writes to refute those who would set aside the Catholic Church as not representative of the teaching of Christ, by quoting at length the long list of Popes stretching from his own time to the days of Saint Peter, who first ruled the Church from Rome; and, of course, from the date of Saint Augustine in the fifth century to our own it is not difficult to gather from public records the actual names. But really this requires more knowledge and more leisure than can be expected from any of us. It might not, indeed, take much time to compile the list, but it would take a good deal to be certain of each pontiff, whether he did actually follow in the steps of the preceding Popes, and whether he did actually connect his own generation to the one that had gone before. But it is necessary all the same that we should be able to see how this direct lineage can be traced back to the apostolic age. Perhaps the simplest way of all is to take the negative side, and explain that there is no evidence that we can see or have ever heard of to prove that at any one time the succession ceased. In other religions that boast the Christian name we can state at what definite date they came into existence: we can tell almost the very day when the world first saw them or knew them as religious establishments. But only of the Catholics we can say this, that popular speech calls them the "Old Religion." Now, if our Blessed Lord did come to found a Church, it must have been intended to be continuous; but there is one only Church that can even pretend to make this claim. Therefore we have a right to suppose without further proof that it alone is the Church of Christ.
I belong, then, to this Church, and can thus claim kinship with the Apostles. I should not look upon this as mere spiritual snobbery, a craving to find myself well-connected; it has a far deeper significance than that. But there is this lesson to be learnt even from that view of it. The bearer of a noble name must surely take care that nothing base is ever attached to that of which he is but the trustee. He must see to it that no act of his ever reflects evil upon that which was delivered to him not only unsullied, but even glorious. Mindful, therefore, of the apostolic kinship that is mine, I must needs be careful that so high an honour is not made ridiculous by its association with my own disgrace. Moreover, there is this also to be said, that not merely should the sense of high lineage keep me from evil, by associating me with those greater than myself, but the sense of greatness is the best incentive to greatness. When I realize what God has done for me, it shows me more the value of my own life, and in consequence I shall take more pains over my soul. If I thought that God did not much care whether I followed Him or not, that He was too occupied with the vastness of the universe to spare much time for the single units that compose it, I should indeed be little worthy of blame in making no attempts to love or serve Him. But when I see by what myriad chains He has bound me to Himself when I realize that even after He had ascended to His Father, our Lord still wished to keep me close to Himself in the Church, and that this closeness is symbolized by the bond of apostolic union carefully preserved then I love Him, for He evidently is at pains to gain my love.
- text taken from by Father Bede Jarrett, O.P.