All men who think about religion would quite easily agree that once they were really convinced of any doctrine that it had been revealed by God, they would have no difficulty in accepting it. It does not matter how impossible a thing might sound, or how con tradictory it might appear to the other revelations from God: so long as there could be absolute certainty that God had actually revealed it, we should be bound to believe it. For God is the sovereign truth; He cannot either deceive or be deceived: consequently whatever He says we may be certain does represent truth. But the trouble is not this. We would accept whatever God said; the difficulty is to discover what He has said, or, rather, to be convinced that the doctrines put forward as His by the religions of the world do really stand for His teaching. Presumably every creed that has been imposed on the human spirit since the world began, even if it was the faith of only one soul, would have been accepted only because that soul was assured that it was the revealed word of God. If I am convinced that God has revealed anything, I must accept it; but how am I to find out what He has revealed? All religions come to me, and each tells me that theirs is the true Church of God, or that there is no Church at all. Each, that is, gives an entirely different list of the articles to which it demands my assent, yet each claims that it alone represents the real teaching of God, as revealed in Christ. No doubt some in these times would not in theory exclude other religions from a share in divine inspiration, but the incessant war that they wage on each other shows that in practice they hardly recognize the claims of the others.
Now, for purposes of convenience, we can divide all religions of the world into three classes those which, when asked for the supreme rule for discovering what God has revealed, would present the inquirer with a book; those who would tell him to look within at his conscience; those who would tell him to look without at some external authority. The first set (Evangelicals and Mohamedans) are really reducible to the second (Nonconformists and Agnostics), for the interpretation of the book with them lies finally with the con science. Hence we have two main divisions: those who say "look within to conscience"; those who say "look without to authority." Now, the first set cannot be right, if it is granted that there is such a thing at all as truth; for if the conscience is the real test of truth, how is it that conscientious men differ? If I am to look into my own heart to find out whether Christ is God or not, whether divorce and remarriage is allowed or not, and if my decision (as these people imply) will really be the true answer, how comes it that there are any differences at all in the world? But if they answer that they do not mean that it is right in itself, but that it is right for me to follow my conscience, then our obvious answer is that in this case, if they do not pretend to be able to find truth at all, what is the use of their calling themselves a religion? Surely they have no business to pretend to teach what they do not know to be right. It is presumptuous in the extreme, as well as very wicked, for a preacher to endeavour to tell people what he is not sure is true. He ought to leave them to their own consciences and not dare to interfere with the direct inspiration of God.
All this is not intended to be controversial, but to let me see what exactly I mean to myself when I proclaim my belief in the authority of the Church. It means that I am convinced that she is the divine representative of God on earth, and that when she announces to me any doctrine concerning faith or morals, then I am bound to accept it not because I understand it or approve of it, but because it is the very revelation of God. For if there is such a thing as truth to be got on earth (and our Lord evidently thought so when He commanded the apostles to "teach"), then I can be certain that nowhere else is it obtainable than within the borders of the Catholic Church. Other religions may retain fragments of truth, but she alone has the whole truth. I must, of course, convince myself by every means in my power that she does stand for the Church that Christ came to found that grew up in the days of the apostles and has lasted as a living and deciding voice for so many centuries. I have first to be convinced of that, and then I believe quite simply whatever after that she tells me is the faith once delivered to the saints. To follow his conscience is all that is demanded of any man, but each is obliged to find out where the truth is, that through the truth he may reach God. For me, then, by the Divine Mercy, the way of truth has been made manifest, and I have, therefore, to be thankful for the wonderful favour shown me; and my best way of showing my gratitude is by seeking always to see in the Creed the actual story of God, as told me by Himself. I must look on the Church as just His mouthpiece. There is compulsion in truth, and from it no one may swerve; but if there is compulsion, there is also liberty, for it is only the truth than can make us free.
- text taken from Meditations for Layfolk by Father Bede Jarrett, O.P.