Litotes (Deminutio) (figure of thought, Rhet. Her. 4.38.50): The figure in which we say that by nature, fortune, or diligence, we or our clients possess some exceptional advantage, and, in order to avoid the impression of arrogant display, we moderate and soften the statement of it; e.g., “This, men of the jury, I have the right to say—that by our labor and diligence I have contrived to be no laggard in the mastery of military science.” (Use of “no laggard” instead of saying that he was “the best.”).
When Paul is arrested in Acts 21, he uses this figure when describing himself.
Acts 21:39 εἶπεν δὲ ὁ Παῦλος· ἐγὼ ἄνθρωπος μέν εἰμι Ἰουδαῖος, Ταρσεὺς τῆς Κιλικίας, οὐκ ἀσήμου πόλεως πολίτης· δέομαι δέ σου, ἐπίτρεψόν μοι λαλῆσαι πρὸς τὸν λαόν.Now, look at the NRSV translation:
Acts 21:39 Paul replied, “I am a Jew, from Tarsus in Cilicia, a citizen of an important city; I beg you, let me speak to the people.”The NRSV translates οὐκ ἀσήμου πόλεως πολίτης as "a citizen of an important city" and the sense is correct, but they have totally missed the importance of the figure of speech litotes and therefore the power of the words. Literally, this phrase should be translated, "a citizen of a not insignificant city." The effect is that of a double negative, essentially a positive. Paul is claiming that his home town, Tarsus, was indeed important. But, by using the figure litotes, Luke highlights the importance of Paul's city, the upstanding nature of Paul himself. The fact that this figure is used draws more attention to the credentials of Paul than if no figure had been used.
