Any harm you do to a man should be done in such a way that you need not fear his revenge.
Niccolo MachiavelliA prudent man should always follow in the path trodden by great men and imitate those who are most excellent, so that if he does not attain to their greatness, at any rate he will get some tinge of it.
Niccolo MachiavelliTherefore, a prudent ruler ought not to keep faith when by so doing it would be against his interest, and when the reasons which made him bind himself no longer exist. If men were all good, this precept would not be a good one; but as they are bad, and would not observe their faith with you, so you are not bound to keep faith with them.
Niccolo MachiavelliThe reason is that nature has so created men that they are able to desire everything but are not able to attain everything: so that the desire being always greater than the acquisition, there results discontent with the possession and little satisfaction to themselves from it. From this arises the changes in their fortunes; for as men desire, some to have more, some in fear of losing their acquisition, there ensues enmity and war, from which results the ruin of that province and the elevation of another.
Niccolo Machiavelli