The Early Christian was very precisely a person carrying about a key, or what he said was a key. The whole Christian movement consisted in claiming to possess that key. It was not merely a vague forward movement, which might be better represented by a battering-ram. It was not something that swept along with it similar or dissimilar things, as does a modern social movement. As we shall see in a moment, it rather definitely refused to do so. It definitely asserted that there was a key and that it possessed that key and that no other key was like it; in that sense it was as narrow as you please. Only it happened to be the key that could unlock the prison of the whole world; and let in the white daylight of liberty.
The creed was like a key in three respects; which can be most conveniently summed up under this symbol. First, a key is above all things a thing with a shape. It is a thing that depends entirely upon keeping its shape. The Christian creed is above all things the philosophy of shapes and the enemy of shapelessness. That is where it differs from all that formless infinity, Manichean or Buddhist, which makes a sort of pool of night in the dark heart of Asia; the ideal of uncreating all the creatures. That is where it differs also from the analogous vagueness of mere evolutionism, the idea of creatures constantly losing their shape. A man told that his solitary latchkey had been melted down with a million others into a Buddhistic unity would be annoyed. But a man told that his key was gradually growing and sprouting in his pocket, and branching into new wards or complications, would not be more gratified.
Second, the shape of a key is in itself a rather fantastic shape. A savage who did not know it was a key would have the greatest difficulty in guessing what it could possibly be. And it is fantastic because it is in a sense arbitrary. A key is not a matter of abstractions; in that sense a key is not a matter of argument. It either fits the lock or it does not. It is useless for men to stand disputing over it, considered by itself; or reconstructing it on pure principles of geometry or decorative art. It is senseless for a man to say he would like a simple key; it would be far more sensible to do his best with a crowbar.
And thirdly, as the key is necessarily a thing with a pattern, so this was one having in some ways a rather elaborate pattern. When people complain of the religion being so early complicated with theology and things of the kind, they forget that the world had not only got into a hole, but had got into a whole maze of holes and corners. The problem itself was a complicated problem; it did not in the ordinary sense merely involve anything so simple as sin. It was also full of secrets, of unexplored and unfathomable fallacies, of unconscious mental diseases, of dangers in all directions. If the faith had faced the world only with the platitudes about peace and simplicity some moralists would confine it to, it would not have had the faintest effect on that luxurious and labyrinthine lunatic asylum. What it did do we must now roughly describe; it is enough to say here that there was undoubtedly much about the key that seemed complex, indeed there was only one thing about it that was simple. It opened the door.
— The Everlasting Man (1925).