IT will be admitted by most Christians that if the Atonement, quite apart from precise definitions of it, is anything to the mind, it is everything. It is the most profound of all truths, and the most recreative. It determines more than anything else our conceptions of God, of man, of history, and even of nature; it determines them, for we must bring them all in some way into accord with it. It is the inspiration of all thought, the impulse and the law of all action, the key, in the last resort, to all suffering. Whether we call it a fact or a truth, a power or a doctrine, it is that in which the differentia of Christianity, its peculiar and exclusive character, is specifically shown; it is the focus of revelation, the point at which we see deepest into the truth of God, and come most completely under its power. For those who recognize it at all it is Christianity in brief; it concentrates in itself, as in a germ of infinite potency, all that the wisdom, power and love of God mean in relation to sinful men.
From James Denny's classic book, The Death of Christ