Pelopidas (1.5-2.1)

For this reason Homer always brings his boldest and most valiant heroes into battle well armed and equipped; and the Greek lawgivers punish him who casts away his shield, not him who throws down his sword or spear, thus teaching that his own defence from harm, rather than the infliction of harm upon the enemy, should be every man’s first care, and particularly if he governs a city or commands an army.

For if, as Iphicrates analyzed the matter, the light-armed troops are like the hands, the cavalry like the feet, the line of men-at-arms itself like chest and breastplate, and the general like the head, then he, in taking undue risks and being over bold, would seem to neglect not himself, but all, inasmuch as their safety depends on him, and their destruction too. Therefore Callicratidas, although otherwise he was a great man, did not make a good answer to the seer who begged him to be careful, since the sacrificial omens foretold his death; Sparta, said he, does not depend upon one man.