Spend your leisure time in cultivating an ear attentive to discourse, for in this way you will find that you learn with ease what others have found out with difficulty.

Consider that nothing in human life is stable; for then you will not exult overmuch in prosperity, nor grieve overmuch in adversity. Rejoice over the good things which come to you, but grieve in moderation over the evils which befall you.

Whetstones are not themselves able to cut, but make iron sharp and capable of cutting.

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.

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.

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.

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