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.

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

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.

Never hope to conceal any shameful thing which you have done; for even if you do conceal it from others, your own heart will know. … Pursue the enjoyments which are of good repute; for pleasure attended by honor is the best thing in the world, but pleasure without honor is the worst.

Be gracious to all men, but choose the best to be your friends.

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.

It is more important to know where you are going than to get there quickly. Do not mistake activity for achievement. Remember that there is nothing stable in human affairs, therefore avoid undue elation in prosperity or undue depression in adversity.