History of the Peloponnesian War

When he found this, he told them not to be led away by tales, but ratter to send men of their own body who were of good character, and would bring back a credible report after inspection.

They despatched them therefore; and Themistocles secretly sent directions about them to the Athenians, to detain them, with as little appearance of it as possible, and not to let them go until they themselves had returned back; (for by this time his colleagues, Abronychus, the son of Lysicles, and Aristides, the son of Lysimachus, had also come to him with the news that the wall was sufficiently advanced;) for he was afraid that the Lacedaemonians, when they heard the truth, might not then let them go.

So the Athenians detained the ambassadors, as was told them; and Themistocles, having come to an audience of the Lacedaemonians, then indeed told them plainly that their city was already walled, so as to be capable of defending its inhabitants; and if the Lacedaemonians or the allies wished to send any embassy to them, they should in future go as to men who could discern what were their own and the general interests.