History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
And the Athenians are even more likely than most men to act in this way, since they are more disposed to claim the right to rule over others and to attack and ravage their neighbours' land than to see their own ravaged.
Realising, then, how powerful is the city against which you are taking the field, and how great is the fame, for better or for worse, which you are about to win for your ancestors and for yourselves fiom the outcome, follow wherever your officers lead you, regarding good order and vigilance as all-important, and sharply giving heed to the word of command; for this is the fairest as well as the safest thing—for a great host to show itself subject to a single discipline."
With these words Archidamus dismissed the assembly. He then first sent Melesippus son of Diocritus, a Spartan, to Athens, in the hope that the Athenians, when they saw that the Lacedaemonians were already on the march, might be somewhat more inclined to yield.