“You, Socrates, began by saying that virtue can't be taught, and now you are insisting on the opposite, trying to show that all things are knowledge, justice, soundness of mind, even courage, from which it would follow that virtue most certainly can be taught.”
As quoted in Protagoras by Plato
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Protagoras 6
pre-Socratic Greek philosopher -486–-411 BCRelated quotes

“The strangest, most generous, and proudest of all virtues is true courage.”
Attributed

“Consider your origin;
you were not born to live like brutes,
but to follow virtue and knowledge.”
Canto XXVI, lines 118–120.
The Divine Comedy (c. 1308–1321), Inferno

“Courage is the ladder on which all the other virtues mount. ”
“Where there is no joy there can be no courage; and without courage all other virtues are useless.”
"Water", p. 113; this is often quoted as simply: Without courage, all other virtues are useless. <!-- Confessions of a Barbarian: Selections from the Journals of Edward Abbey, 1951-1989 (1994) p. 207 -->
Source: Desert Solitaire (1968)
Context: Has joy any survival value in the operations of evolution? I suspect that it does; I suspect that the morose and fearful are doomed to quick extinction. Where there is no joy there can be no courage; and without courage all other virtues are useless.