"If you treat an individual as he is, he will remain as he is. But if you treat him as if he were what he ought to be and could be, he will become what he ought to be and could be."

"The truly wise man is he who knows that he knows nothing."

"Behavior is a mirror in which everyone displays his own image."

"Thinking is easy, acting is difficult, and to put one's thoughts into action is the most difficult thing in the world."

"He who cannot give an account of three thousand years of history remains in darkness, inexperienced, and lives from day to day."