Man has, as it were, become a kind of prosthetic God. When he puts on all his auxiliary organs, he is truly magnificent but those organs have not grown on him and they still give him much trouble at times.

You must not fight too often with one enemy, or you will teach him all your art of war.

No change of circumstances can repair a defect of character.

If you want to increase your success rate, double your failure rate.

If I had more time, I would have written you a shorter letter.

Your net worth to the world is usually determined by what remains after your bad habits are subtracted from your good ones.