The first opinion which one forms of a prince, and of his understanding, is by observing the men he has around him; and when they are capable and faithful he may always be considered wise, because he has known how to recognize the capable and to keep them faithful. But when they are otherwise one cannot form a good opinion of him, for the prime error which he made was in choosing them.

Ch. 22. Variant translation: The first method for estimating the intelligence of a ruler is to look at the men he has around him. - The Prince (1513) [as translated by W. K. Marriott]