so men, who through prosperity have become restive and over self-confident, ought to be put into the training-ring, so to speak, of reason and learning, that they may be brought to comprehend the frailty of human affairs and the fickleness of fortune.
 Marcus Tullius Cicero, On Duties (44 BC). copy citation

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Author Marcus Tullius Cicero
Source On Duties
Topic fickleness frailty
Date 44 BC
Language English
Reference
Note Translated by Walter Miller
Weblink http://www.constitution.org/rom/de_officiis.htm

Context

“Panaetius tells us that Africanus, his pupil and friend, used to say: "As, when horses have become mettlesome and unmanageable on account of their frequent participation in battles, their owners put them in the hands of trainers to make them more tractable; so men, who through prosperity have become restive and over self-confident, ought to be put into the training-ring, so to speak, of reason and learning, that they may be brought to comprehend the frailty of human affairs and the fickleness of fortune." {91} The greater our prosperity, moreover, the more should we seek the counsel of friends, and the greater the heed that should be given to their advice. Under such circumstances also we must beware of lending an ear to sycophants or allowing them to impose upon us with their flattery.” source