Was the Apostle Paul effective as a public speaker or not? Was Paul’s facility in rhetoric strong or weak? New Testament scholars disagree on how to answer this question. Here is a possible solution that I recently proposed in my book, Paul’s Thorn in the Flesh: New Clues for an Old Problem (pages 135-137):
The eighth and final consideration from the discourse of 2 Cor. 10-13 is the possible connection of Paul’s thorn to the Corinthians’ disparagement of Paul’s speaking ability. The reader at this point will be well aware that we are already moving in the direction of viewing Paul’s thorn as something physical that has to do with his face. But is there any connection to the rhetorical issues that are also important in the discourse? In 2 Cor. 10-13, the weakness of Paul’s rhetorical ability can be inferred at various points and is explicitly referenced in a few spots. For example, in 2 Cor. 10:10 Paul’s detractors have apparently claimed that Paul’s “speech is of no account.” For the sake of argument, Paul grants the premise that he is a poor speaker when he says, “Even if I am unskilled in speaking, I am not so in knowledge.” (2 Cor. 11:6) He may also allude to their criticisms of his rhetoric when he says, “so that no one may think more of me than he … hears from me” (2 Cor. 12:6).
But this presents a problem for New Testament scholars. Pauline scholars find themselves in a quandary about how to speak about Paul’s rhetorical ability. They struggle to answer the question of how Paul seemed so familiar with rhetoric that he could persuade multiple listeners to accept his message on the one hand, and how he could be criticized for being a poor speaker on the other. Ben Witherington is one example of a scholar who was so impressed by Paul’s knowledge of rhetoric that he organized his commentary on the Corinthian letters around ancient rhetorical categories. But it also appears that detractors in Corinth criticized Paul for his rhetoric — to such a degree that Paul felt the need to defend himself. How shall we resolve this dilemma? Was Paul an effective rhetorician or not?
In anticipation of a solution, what if Paul’s speaking was occasionally interrupted by brief, but excruciating, bouts of stabbing craniofacial pain? Paul, then, could be at the same time a powerful and persuasive speaker, but would still have found himself open to criticism about his speaking presentation. This especially would have been the case if his listeners thought that the shooting pain that brought him to his knees for a few seconds, or up to a minute or two, was an attack of black magic. Would not that have engendered criticism of Paul’s speaking ability in first-century Corinth, even if Paul was rhetorically adept?
At this point, we need to find a way to reconcile Paul’s apparent facility with rhetoric — enough to convince scores of people to follow his message — with the fact that he was being criticized for his poor rhetoric. The suggestion put forth here is that a possible resolution is found in the nature of Paul’s thorn in the flesh — sudden jabs of facial pain that sometimes interrupted his speaking (and that would have been viewed as attacks of black magic by many), and thus would have made him less effective as a communicator than he otherwise could have been.
 Thrall is representative of the struggle, but not alone in it, in her discussion of 10:10. See Margaret E Thrall, 2 Corinthians 8-13, vol. 2 of A Critical and Exegetical Commentary on The Second Epistle to the Corinthians, ICC (London and New York: T&T Clark, 2000), 631-633.
 Witherington suggests that Paul used “Attic or Roman plain style, rather than the more verbose Asiatic style,” and “resolved not to declaim the gospel…, that is, not to use Sophistic or ornamental rhetoric in his missionary preaching.” Ben Witherington III, Conflict & Community in Corinth: A Socio-Rhetorical Commentary on 1 and 2 Corinthians (Grand Rapids: Eerdmans and Carlisle: Paternoster),46. For another application of rhetorical categories to 2 Corinthians, see James W. Thompson, Apostle of Persuasion: Theology and Rhetoric in the Pauline Letters (Grand Rapids: Baker, 2020), 156-167. For an introduction to rhetorical categories for the study of the New Testament see Ben Witherington III, New Testament Rhetoric: An Introductory Guide to the Art of Persuasion in and of the New Testament (Eugene, OR: Cascade Books, 2009) and Mikeal C. Parsons and Michael Wade Martin, Ancient Rhetoric and the New Testament: The Influence of Elementary Greek Composition (Waco, TX: Baylor University Press, 2018), the last of which emphasizes the important role of the progymnasmata (elementary lessons in rhetoric) for understanding the influence of rhetoric on New Testament authors.
 See Ryan S. Schellenberg, Rethinking Paul’s Rhetorical Education: Comparative Rhetoric and 2 Corinthians, ECL (Atlanta: Society of Biblical Literature, 2013), 17-56 for a history of the use of rhetorical categories in the interpretation of Paul’s letters, particularly focusing on the question of whether Paul was formally trained in rhetoric. Note that Schellenberg himself (focusing on 2 Corinthians 10-13) argues that Paul was not formally trained in rhetoric, though Paul still used informal rhetorical devices effectively.
 Note Quintilian’s comment in his rhetorical instructions (11.3.69-71): “It is the head which occupies the chief place in Delivery (as it does in the body itself)….” Cited in Wenhua Shi, Paul’s Message of the Cross as Body Language, WUNT 2, Reihe 254 (Tübingen: Mohr Siebeck, 2008), 138. Also, “But the face is sovereign. It is this that makes us humble, threatening, flattering, sad, cheerful, proud, or submissive; men hang on this; men fix their gaze on this; this is watched even before we start to speak; this makes us love some people and hate others; this makes us understand many things; this often replaces words altogether.” Cited in Beatrice da Vela, “From the Stage to the Court: Rhetorical and Dramatic Performance in Donatus’ Commentary on Terence,” in The Theatre of Justice: Aspects of Performance in Greco-Roman Oratory and Rhetoric, ed. Sophia Papaioannou, et. al., MNS 403 (Leiden: Brill, 2017), 164 n. 4.
 Dale B. Martin, The Corinthian Body (New Haven, CT: Yale University Press, 1995): 54 comments that Paul’s critics in 2 Cor 10-13 would have drawn a connection between his body and his rhetoric and character, “His critics point to his weakness of body (whether due to illness, disfigurement, or simply constitutional infirmity) as irrefutable evidence of weakness of character.”
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