The nature of man is such that people consider themselves put under an obligation as much by the benefits they confer as by those they receive.
Niccolo MachiavelliSometimes it has been of great moment while the fight is going on, to disseminate words that pronounce the enemies' captain to be dead, or to have been conquered by another part of the army. Many times this has given victory to him who used it.
Niccolo MachiavelliA prince... must learn from the fox and the lion... One must be a fox in order to recognize traps, and a lion to frighten off wolves. Those who act simply as lions are stupid. So it follows that a prudent ruler cannot, and must not, honour his word when it places him at a disadvantage and when the reasons for which he made his promise no longer exist.
Niccolo Machiavelli