But in doing this we must put the emphasis of our preaching to-day where it belongs, where Christ puts it, on the doctrines that are most important to human life and happiness. We can afford to let the fine metaphysical distinctions of theology rest for a while, and throw all our force on the central, fundamental truths which give steadiness and courage and cheer to the heart of man. I will not admit that it makes no difference to a man of this age whether or not he believes in the personal God and the Divine Christ. If he really believes, it makes all the difference between spiritual strength and spiritual weakness, between optimism and pessimism. I will not admit that it makes no difference to a learned scholar or a simple labourer to-day whether he accepts or ignores the doctrine of the atonement, the doctrine of personal immortality. If he knows that Christ died for him, that there is a future beyond the grave, it makes all the difference between despair and hope, between misery and consolation, between the helpless frailty of a being that is puffed out like a candle, and the joyful power of an endless life. My brethren, we must work and pray for a true revival of Christian doctrine in our age. We must deepen our own hold upon the truths which Christ has taught us. We must preach them more simply, more confidently, more reasonably, more earnestly. We must draw from them the happiness and the help, the comfort and the inspiration, that they have to give to the souls of men. But most of all, we must keep them in close and living touch with the problems of daily duty and experience. For no doctrine, however high, however true, can make men happy until it is translated into life. ii. Here is the second if, on which the power of religion to confer happiness depends: If ye know, happy are ye if ye do these things. Between the knowing and the doing there is a deep gulf. Into that abyss the happiness of many a man slips, and is lost. There is no peace, no real and lasting felicity for a human life until the gulf is closed, and the continent of conduct meets the continent of creed, edge to edge, lip to lip, firmly joined forever. It is not a blessing to know the things that Christ teaches, and then go on living as if they were false or doubtful. It is a trouble, a torment, a secret misery. To know that God is our Father, and yet to withhold our love and service from Him; to know that Christ died for us, and yet to deny Him and refuse to follow Him; to know that there is an immortal life, and yet to waste and lose our souls in the pursuit of sensual pleasure and such small portion of the world as we may hope to gain,--surely that is the deepest of all unhappiness. But the right kind of knowing carries in its heart the doing of the truth. And the right kind of doing leads to a fuller and happier knowing. "If any man will do God's will," declares Christ, "he shall know of the doctrine."