The scrupulous and the just, the noble, humane, and devoted natures; the unselfish and the intelligent may begin a movement - but it passes away from them. They are not the leaders of a revolution. They are its victims.
It is when we try to grapple with another man's intimate need that we perceive how incomprehensible, wavering, and misty are the beings that share with us the sight of the stars and the warmth of the sun.
Some great men owe most of their greatness to the ability of detecting in those they destine for their tools the exact quality of strength that matters for their work.