The instruction of the foolish is a waste of knowledge; soap cannot wash charcoal white. [ Kabir ]

There are many persons of combative tendencies, who read for ammunition, and dig out of the Bible iron for balls. They read, and they find nitre and charcoal and sulphur for powder. They read, and they find cannon. They read, and they make portholes and embrasures. And if a man does not believe as they do, they look upon him as an enemy, and let fly the Bible at him to demolish him. So men turn the word of God into a vast arsenal, filled with all manner of weapons, offensive and defensive. [ H. W. Beecher ]

Greatness is not a teachable nor gainable thing, but the expression of the mind of a God-made man: teach, or preach, or labour as you will, everlasting difference is set between one man's capacity and another's; and this God-given supremacy is the priceless thing, always just as rare in the world at one time as another.... And nearly the best thing that men can generally do is to set themselves, not to the attainment, but the discovery of this: learning to know gold, when we see it, from iron-glance, and diamond from flint-sand, being for most of us a more profitable employment than trying to make diamonds of our own charcoal. [ John Ruskin ]