Quintilian, and J.S. Watson. Institutes of Oratory.Edited by Lee Honeycutt, 2010. Kindle Electronic Edition. Book IV Chapter 3.
Quintilian, having discussed the statement of the case, moves on to the subject of digressions. “It is the custom of most speakers, when the order of facts is set forth, to make a digression to some pleasing and attractive moral topic, so as to secure as much favorable attention as possible from the audience” (Quintilian IV.3.1). Though it is not necessary and may prove distracting from the case, a digression, used carefully, can be of great value (Quintilian IV.3.4). Quintilian adduces numerous examples of such digressions drawing the interest and sympathy of the judges rather than distracting from the case.