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 when we are defending, there should always be an increase of force in the treatment of questions and we should proceed from the weaker to the stronger, whether the points we raise are of the same or of a different character.