Any cause, any ambition, any great endeavor that can stir the blood, and give a life direction, purpose, and continuity of achievement, has the power to rescue life from ennui, from emptiness, and give it positive worth. But most ambitions pall in time, and many a cause that has taken a man's best energies has come to seem mistaken or futile with the years. There is only one great campaign which is so eternal, so surely necessary, so clear in its summons to all men, that the heart can rest in it as in something great enough to ennoble a whole life. That is the age-long war against evil, the unending summons to duty, the service of God. Once a man learns this deepest of joys, nothing can take it from him; whatever his limitations, however narrow his sphere, there will not fail to be a right way, a brave way, a beautiful way to live. There is comradeship in it; in this common service of God - or of good, if we must avoid religious terms - we stand shoulder to shoulder with the saints and heroes of all races and times, with all, of whatever land or tongue, who are striving to push forward the line, to make the right prevail and banish evil. Every effort, every sacrifice, has its inextinguishable effect; in his moral conquests a man is no longer an individual, he is a part of the great tide that is resistlessly making toward the better world of the future, the Kingdom of God. The great Power in the world that makes for righteousness is back of him, and in him; in no loyal moment is he alone. . . . Inevitably the tongue slips into religious language in dealing with these high truths; but nonetheless are they scientific truths, matters of plain every day observation.