Gentlemen, it is religion, the love of God and neighbour, which gives life a meaning; knowledge cannot do it. Let me, if you please, speak of my own experience, as one who for thirty years has taken an earnest interest in these things. Pure knowledge is a glorious thing, and woe to the man who holds it light or blunts his sense for it. But to the question, Whence, whither, and to what purpose, it gives an answer to-day as little as it did two or three thousand years ago. It does, indeed, instruct us in facts; it detects inconsistencies; it links phenomena; it corrects the deceptions of sense and idea. But where and how the curve of the world and the curve of our own life begins—that curve of which it shows us only a section—and whither this curve leads, knowledge does not tell us. But if with a steady will we affirm the forces and the standards which on the summits of our inner life shine out as our highest good, nay, as our real self; if we are earnest and courageous enough to accept them as the great Reality and direct our lives by them; and if we then look at the course of mankind’s history, follow its upward development, and search, in strenuous and patient service, for the communion of minds in it, we shall not faint in weariness and despair, but become certain of God, of the God whom Jesus Christ called his Father, and who is also our Father.

From Adolf Harnack, What Is Christianity?, Translated by Thomas Bailey Saunders