Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.

I know the hatred and envy of your hearts. Ye are not great enough not to know of hatred and envy. Then be great enough not to be ashamed of them!

When a hundred men stand together, each of them loses his mind and gets another one.

Ah, how little you know of human happiness - you comfortable and benevolent people! For happiness and unhappiness are brother and sister - or even twins who grow up together - or in your case - remain small together!

One often contradicts an opinion when what is uncongenial is really the tone in which it was conveyed.

To escape boredom, man works either beyond what his usual needs require, or else he invents play, that is, work that is designed to quiet no need other than that for working in general.

I teach the No to all that makes weak--that exhausts. I teach the Yes to all that strengthens, that stores up strength, that pride.