Vae victis

Woe to the Vanquished

Brennus

Brennus statement, made as a Gallic conqueror, is true in more sense than one, not as a brazen command upon the defeated, but as an existential fact.

Of course, in keeping with the nature of fate, which we've had some quotes on recently, while Brennus sacked Roman and generally acted like a bady, his troops came down with the trots in the city and the Romans ended up tossing him and followers out rather effectively somewhat later.  That may say about as much on this topic as the quote itself.