In a conversation that Luther had one day with some friends at table, he spoke of the world as a vast and magnificent pack of cards composed of emperors, kings, princes and so forth. For several ages these had been vanquished by the Pope. Then God had come upon the scene, and chosen the “ace,” the very smallest card in the pack--himself, in a word--and overthrown this conqueror of worldly powers and principalities. Mohammed, as much as Luther, was one of “God’s Aces.” Seldom, indeed, in the history of the world, has so great a human river flowed from a source so puny. Never did the divine manifest itself in a single pip, so seemingly small and insignificant as a cause, yet so pre-eminently and consistently great as an effect! “Men,” says Dumas in one of his historico-romantic masterpieces, “are visible, palpable, moral. You can meet, attack, subdue them; and when they are subdued you can subject them to trial and hang them. But ideas you cannot oppose in that way. They glide unseen; they penetrate; they hide themselves especially from the sight of those who would destroy them. Hidden in the depths of the soul, they there throw out deep roots. The more you cut off the branches which imprudently appear, the more powerful and inextirpable become the roots below. “An idea is a young giant which must be watched night and day; for the idea which yesterday crawled at your feet, to-morrow will dispose of your head. An idea is a spark falling upon straw.” ... “For the mind of man is no inert receptacle of knowledge, but absorbs and incorporates into its own constitution the ideas which it receives.” Thus it was with Mohammed. God was the spark, the vital spark of spiritual flame, and this humble but honest Arab trader was the straw, that after twenty years of silent but tenacious smouldering God had set a light to.