I have just finished reading The Prince by Niccolò Machiavelli. He wrote in the 16th century to a powerful Italian ruler to instruct him in the realpolitik of starcraft, ie how a ruler can keep power and avoid losing it. Machiavelli rejected all Divine law (Christian or Muslim) and traditional values advocating instead some pretty ruthless tactics.
There are many jucy passages I could quote but this one on page 57 is typical. The chapter is headed:
How princes should honour their word
‘A prince, therefore, need not necessarily have all the good qualities I mentioned above, but he should certainly appear to have them. I would even go so far as to say that if he has these qualities and always behaves accordingly he will find them harmful; if he only appears to have them they will render him service. He should appear to be compassionate, faithful to his word, kind, guileless, and devout. And indeed he should be so. But his disposition should be such that, if he needs to be the opposite, he knows how.’
‘You must realise this: that a prince, and especially a new prince, cannot observe all those things which give men a reputation for virtue, because in order to maintain his state he is often forced to act in defiance of good faith, of charity, of kindness, of religion. And so he should have a flexible disposition, varying as fortune and circumstances dictate. As I said above, he should not deviate from what is good, if that is possible, but he should know how to do evil, if that is necessary.’
For more on the author and his book go here