It is not in human nature to be indifferent to political power; and if the price men have to pay for it is the sacrifice of friendship, they think their treason will be thrown into the shade by the magnitude of the reward.
 Marcus Tullius Cicero, On Friendship (44 BC). copy citation

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Author Marcus Tullius Cicero
Source On Friendship
Topic friendship sacrifice
Date 44 BC
Language English
Reference
Note Translated by E. S. Shuckburgh
Weblink http://www.gutenberg.org/files/2808/2808-h/2808-h.htm

Context

“But even if some are found who think it mean to prefer money to friendship, where shall we look for those who put friendship before office, civil or military promotions, and political power, and who, when the choice lies between these things on the one side and the claims of friendship on the other, do not give a strong preference to the former? It is not in human nature to be indifferent to political power; and if the price men have to pay for it is the sacrifice of friendship, they think their treason will be thrown into the shade by the magnitude of the reward. This is why true friendship is very difficult to find among those who engage in politics and the contest for office. Where can you find the man to prefer his friend's advancement to his own? And to say nothing of that, think how grievous and almost intolerable it is to most men to share political disaster.” source