Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
Consequently those vivid conceptions of which I spoke [*](VI. ii. 29.) and which, as I remarked, are called φαντασίαι, together with everything that we intend to say, the persons and questions involved, and the hopes and fears to which they give rise, must be kept clearly before our eyes and admitted to our hearts: for it is feeling and force of imagination that make us eloquent. It is for this reason that even the uneducated have no difficulty in finding words to express their meaning, if only they are stirred by some strong emotion.
Further the attention of the mind must be directed not to some one thing, but simultaneously to a number of things in continuous sequence. The result will be the same as when we cast our eyes along some straight road and see at once all that is on and near it, obtaining a view not merely of its end, but of the whole way there. Dread of the shame of failure is also a powerful stimulant to oratory,
For the sheer necessity of speaking thrusts forward and forces out our labouring thought, and the desire to win approbation kindles and fosters our efforts. So true is it that there is nothing which does not look for some reward, that eloquence, despite the fact that its activity is in itself productive of a strong feeling of pleasure, is influenced by nothing so much as the immediate acquisition of praise and renown.