one should modify one's plans."
"In the practical art of war, the best thing of all is to take the enemy's country whole and intact; to shatter and destroy it is not so good."
"The worst policy of all is to besiege walled cities."
"There is no instance of a country having benefited from prolonged warfare."
"It is only one who is thoroughly acquainted with the evils of war that can thoroughly understand the profitable way of carrying it on."
"The captured soldiers should be kindly treated and kept."
"There are roads which must not be followed, armies which must be not attacked, towns which must not be besieged, positions which must not be contested, commands of the sovereign which must not be obeyed."
"In war, then, let your great object be victory, not lengthy campaigns."
"The general that hearkens to my counsel and acts upon it, will conquer: let such a one be retained in command! The general that hearkens not to my counsel nor acts upon it, will suffer defeat:--
let such a one be dismissed!"
http://en.wikisource.org/wiki/The_Art_of_War_%28Sun%29:hi: goodbye.