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.
for no one was visible on the wall or was seen coming out by the gates, which were all closed. He therefore thought that he had made a mistake in coming up without storming-machines; for he might have taken the town, since it was undefended.
But Brasidas, as soon as he saw the Athenians stirring, went down himself from Cerdylium and entered Amphipolis.
But he did not march out and draw up against the Athenians, because he mistrusted his own force, believing them to be inferior, not in numbers—as they were about equal—but in quality; for the force that was in the field were Athenians of pure blood and the pick of the Lemnians and Imbrians. So he was preparing to attack by means of a stratagem;