History of the Peloponnesian War
Thucydides
Thucydides. The history of the Peloponnesian War, Volume 1-2. Dale, Henry, translator. London: Heinemann and Henry G. Bohn, 1851-1852.
but rather, to assist us, and not to be afraid of their armament. For it is not formidable, if we all take our stand together; but only if, on the contrary, we are separated from each other, which they are so anxious to effect: since even when they came against us alone, and were victorious in battle, they did not achieve what they wished, but quickly went away again.
Surely then, if we were united, it were not reasonable for us to be disheartened: but we ought to enter more heartily into alliance, especially as succours will join us from the Peloponnese also, the inhabitants of which are altogether superior to these men in military matters. And no one should think that forethought of yours to be fair to us, while it is safe for you; I mean your assisting neither party, as being allies of both.