Notes from Wikiquote
Response when asked to name the three most important components of rhetoric. Reported by Cicero, Brutus 142 | Ut verum videretur in hoc illud, quod Demosthenem ferunt ei, qui quaesivisset quid primum esset in dicendo, actionem, quid secundum idem, et idem tertium respondisse. | You can see by his example how all this bears out the truth of the dictum attributed to Demosthenes; who when asked what was first in oratory replied to his questioner, 'action,' what second, 'action,' and again third, 'action.' (tr. G. L. Hendrickson, 1939) | Also reported by pseudo-Plutarch, Lives of the Ten Orators, 845b | ἐρομένου αὐτόν ⟨τινος⟩ τί πρῶτον ἐν ῥητορικῇ, εἶπεν 'ὑπόκρισις'· καὶ τί δεύτερον 'ὑπόκρισις'· καὶ τί τρίτον 'ὑπόκρισις'. | When someone asked him what was the first thing in oratory, he replied "Delivery," and what the second, "Delivery," and the third, "Delivery." (tr. H. N. Fowler, 1936) | Further noted by Quintilian, Institutio Oratoria, XI.3.6 and Longinus, Art of Rhetoric, 195.5–9.