Courage and wisdom are, indeed, rarities amongst men, but of all that is good, a just man it would seem is the most scarce.
 Plutarch, Parallel Lives (c. 100 AD). copy citation

add
Author Plutarch
Source Parallel Lives
Topic rarity wisdom
Date c. 100 AD
Language English
Reference
Note Translated by A. H. Clough
Weblink http://www.gutenberg.org/files/674/674-h/674-h.htm

Context

“And there, no doubt, redoubling their joy, they began to recollect and talk of the state of Greece, what wars she had incurred in defense of her liberty, and yet was never perhaps mistress of a more settled or grateful one that this which other men's labors had won for her: almost without one drop of blood, or one citizen's loss to be mourned for, she had this day had put into her hands the most glorious of rewards, and best worth the contending for. Courage and wisdom are, indeed, rarities amongst men, but of all that is good, a just man it would seem is the most scarce. Such as Agesilaus, Lysander, Nicias, and Alcibiades, knew how to play the general's part, how to manage a war, how to bring off their men victorious by land and sea; but how to employ that success to generous and honest purposes, they had not known.” source