People should either be caressed or crushed. If you do them minor damage they will get their revenge; but if you cripple them there is nothing they can do. If you need to injure someone, do it in such a way that you do not have to fear their vengeance.
Niccolo MachiavelliAlthough deceit is detestable in all other things, yet in the conduct of war it is laudable and honorable; and a commander who vanquishes an enemy by stratagem is equally praised with one who gains victory by force.
Niccolo MachiavelliI hold it to be of great prudence for men to abstain from threats and insulting words towards any one, for neither the one nor the other in any way diminishes the strength of the enemy; but the one makes him more cautious, and the other increases his hatred of you, and makes him more persevering in his efforts to injure you
Niccolo MachiavelliFrom the latter he is defended by being well armed and having good allies, and if he is well armed he will have good friends, and affairs will always remain quiet within when they are quiet without, unless they should have been already disturbed by conspiracy; and even should affairs outside be disturbed, if he has carried out his preparations and has lived as I have said, as long as he does not despair, he will resist every attack.
Niccolo Machiavelli