The speaker should possess the faculties of Invention, Arrangement, Style, Memory, and Delivery. Invention is the devising of the matter, true or plausible, that would make the case convincing. Arrangement is the ordering and distribution of the matter, making clear the place to which each thing is to be assigned. Style is the adaptation of suitable words and sentences to the matter devised. Memory is the firm retention in the mind of the matter, words, and arrangement. Delivery is the graceful regulation of voice, countenance, and gesture (Rhet. Her. 1.2.3).Of these five tasks, the last two are of the least interest to the biblical scholar. NT texts were not ancient speeches. They probably were not memorized in preparation for delivery on a regular basis. Nevertheless, NT texts were written to be read aloud, and thus some things might be noted from a study of the tasks of memory and delivery (right now the source is slipping my mind, but some have argued that the phrase "let the reader understand" in Mark 13:14 is a textual note to the one performing the text to make a certain gesture or to inflect his voice in a specific way while reading this verse).
The first three tasks are very enlightening to biblical critics. One of the primary tools for the task of invention is the topos. A topos, which just means "place" is the rhetorical term for a stock argument or a stock image, or more simply, a "topic.". These are arguments or images that are common and are known to work. Here is a list of topoi from Theon's preliminary exercise of syncrisis: Birth, education, offspring, offices held, reputation, bodily condition, other external conditions, and actions/deeds (expounded upon greatly). Drawing in further categories from Theon’s discussion of encomium, the list also includes the following: city of origin, ancestors, relatives, wealth, health, strength, beauty, virtues (prudence, temperance, courage, justice, piety, generosity, magnanimity), death, and results of death.
Michael Martin has argued that these topoi lists from the progymnasmata served as templates for the writing of the gospels (Michael Martin, "Progymnastic topic lists: a compositional template for Luke and other bioi?" New Testament Studies 54 (2008) 18-41).
Arrangement is also of use for biblical critics. Arrangement dealt with how the rhetorician should lay out his speech. The usual order of arrangement for a speech went like this: an exordium, which was the introduction, the narratio or narration of the facts, the partitio where the speaker would outline his argument, the confirmatio, in which the speaker would give proofs, the refutatio where the rhetorician would refute his opponents, claims, and finally, the exordium or conclusion. This standard arrangement is of some limited use for biblical scholars because NT texts were not ancient forensic speeches. Yet, this type of arrangement has been helpful in analyzing the defense speeches of Paul in Acts. Moreover, the theory behind the task of arrangement can shed light on biblical writers' organization of their material.
A study of the rhetorical task of style, which is my current area of expertise, can be extremely useful to the biblical critic. It is usually in the area of style that Rhetoric gets tagged with all of its pejorative connotations. Because rhetorical style is at the heart of my current NT research, I will create a separate post to talk about its importance to biblical scholarship.