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.
and they regretted not having assented to the treaty. Cleon observing their suspicions of him, with regard to the obstacles thrown in the way of the convention, said that their informants did not speak the truth. When those who had come with the tidings advised them, if they did not believe them, to send some commissioners to see, he himself, with Theogenes, was chosen by the Athenians for that purpose.
Aware therefore that he would be compelled either to give the same account as those whom he was slandering, or to be proved a liar if he gave a different one, he advised the Athenians—seeing that they were really more inclined in their minds for a fresh expedition—that they should not send commissioners, nor delay and waste their opportunity, but sail against the men, if they thought the report was true.
And he pointedly alluded to Nicias the son of Niceratus, who was general at the time; hating him, and tauntingly observing, that it was easy, if their generals were men, to sail with a force and take those in the island; and that if he had himself been in office, he would have done it.
Nicias, observing that the Athenians began to murmur at Cleon for not sailing as it was, if he thought it so easy, and at the same time seeing that he aimed his taunts at him, desired him to take whatever force he chose, as far as the generals were concerned, and make the attempt.