The headword phrase, in the accusative case, derives from Diogenes Laertius 1.30; it then reappears in 1.107, the second chapter of his short biography (1.106-108) of Myson, one of the Seven Sages (c.600 BCE). D.L. is quoting a response, in hexameter verse, from the oracle at Delphi to a questioner -- in some versions, another Sage -- asking whether anyone was wiser than him and being told that Myson was; see J. Fontenrose, The Delphic Oracle (Berkeley & Los Angeles 1978) 293 Q75.
His home village, Chen or Chenai, is variously said to have been on Mt Oita (so e.g. Pausanias 10.24.1) or in Lakonia (so e.g. D.L., Stephanus of Byzantium).