Therefore it was, that Dion, being advertised that Callippus watched all opportunities to take away his life, had never the heart to inquire more particularly into it, saying, that he had rather die than live in that misery, that he must continually stand upon his guard, not only against his enemies, but his friends also;--[Plutarch, Apothegms.]--which Alexander much more vividly and more roundly manifested in effect, when, having notice by a letter from Parmenio, that Philip, his most beloved physician, was by Darius' money corrupted to poison him, at the same time he gave the letter to Philip to read, drank off the potion he had brought him.

Was not this to express a resolution, that if his friends had a mind to despatch him out of the world, he was willing to give them opportunity to do it?
This prince is, indeed, the sovereign pattern of hazardous actions; but I do not know whether there be another passage in his life wherein there is so much firm courage as in this, nor so illustrious an image of the beauty and greatness of his mind.
Those who preach to princes so circumspect and vigilant a jealousy and distrust, under colour of security, preach to them ruin and dishonour: nothing noble can be performed without danger.

I know a person, naturally of a very great daring and enterprising courage, whose good fortune is continually marred by such persuasions, that he keep himself close surrounded by his friends, that he must not hearken to any reconciliation with his ancient enemies, that he must stand aloof, and not trust his person in hands stronger than his own, what promises or offers soever they may make him, or what advantages soever he may see before him.

And I know another, who has unexpectedly advanced his fortunes by following a clear contrary advice.
Courage, the reputation and glory of which men seek with so greedy an appetite, presents itself, when need requires, as magnificently in cuerpo, as in full armour; in a closet, as in a camp; with arms pendant, as with arms raised.
This over-circumspect and wary prudence is a mortal enemy to all high and generous exploits.

Scipio, to sound Syphax's intention, leaving his army, abandoning Spain, not yet secure nor well settled in his new conquest, could pass over into Africa in two small ships, to commit himself, in an enemy's country, to the power of a barbarian king, to a faith untried and unknown, without obligation, without hostage, under the sole security of the grandeur of his own courage, his good fortune, and the promise of his high hopes .-- [ Livy, xxviii.