Institutio Oratoria
Quintilian
Quintilian. Institutio Oratoria, Volume 1-4. Butler, Harold Edgeworth, translator. Cambridge, Mass; London: Harvard University Press, William Heinemann Ltd., 1920-1922.
For the force of eloquence is such that it not merely compels the judge to the conclusion toward which the nature of the facts lead him, but awakens emotions which either do not naturally arise from the case or are stronger than the case would suggest. This is known as deriosis, [*]( Lit. making terrible. ) that is to say, language giving additional force to things unjust, cruel or hateful, an accomplishment in which Demosthenes created immense and special effect.
If I thought it sufficient to follow traditional rules, I should regard it as adequate treatment for this topic to omit nothing that I have read or been taught, provided that it be reasonably sound. But my design is to bring to light the secret principles of this art, and to open up the inmost recesses of the subject, giving the result not of teaching received from others, but of my own experience and the guidance of nature herself.
The prime essential for stirring the emotions of others is, in my opinion,
if we wish to give our words the appearance of sincerity, we must assimilate ourselves to the emotions of those who are genuinely so affected, and our eloquence must spring from the same feeling that we desire to produce in the mind of the judge. Will he grieve who can find no trace of grief in the words with which I seek to move him to grief? Will he be angry, if the orator who seeks to kindle his anger shows no sign of labouring under the emotion which he demands from his audience? Will he shed tears if the pleader's eyes are dry? It is utterly impossible.