Regard as your most faithful friends, not those who praise everything you say or do, but those who criticize your mistakes.

So far has Athens left the rest of mankind behind in thought and expression that her pupils have become the teachers of the world, and she has made the name of Hellas distinctive no longer of race but of intellect, and the title of Hellene a badge of education rather than of common descent.

Always when you are about to say anything, first weigh it in your mind; for with many the tongue outruns the thought.

Let there be but two occasions for speech - when the subject is one which you thoroughly know and when it is one on which you are compelled to speak. On these occasions alone is speech better than silence; on all others, it is better to be silent than to speak.

Those who directed the state in the time of Solon and Cleisthenes did not establish a polity which ... trained the citizens in such fashion that they looked upon insolence as democracy, lawlessness as liberty, impudence of speech as equality, and licence to do what they pleased as happiness, but rather a polity which detested and punished such men and by so doing made all the citizens better and wiser.

And let no one suppose that I claim that just living can be taught for, in a word, I hold that there does not exist an art of the kind which can implant sobriety and justice into depraved natures. Nevertheless, I do think that the study of political discourse can help more than any other thing to stimulate and form such qualities of character

Oratory is good only if it has the qualities of fitness for the occasion, propriety of style, and originality of treatment, while in the case of letters there is no such need whatsoever.