Letters 94.61

There are many who set fire to cities, who storm garrisons that have remained impregnable for generations and safe for numerous ages, who raise mounds as high as the walls they are besieging, who with battering-rams and engines shatter towers that have been reared to a wondrous height. There are many who can send their columns ahead and press destructively upon the rear of the foe, who can reach the Great Sea dripping with the blood of nations; but even these men, before they could conquer their foe, were conquered by their own greed. No one withstood their attack; but they themselves could not withstand desire for power and the impulse to cruelty; at the time when they seemed to be hounding others, they were themselves being hounded.

Seneca, Letters to Lucilius 94.61, translated by Richard Mott Gummere