As I was reading Anthony Thiselton's introduction to 1 Corinthians (1 Corinthians: A Shorter Exegetical & Pastoral Commentary), a light bulb went off in my head (so to speak). I am close to the end of leading a midweek Bible study through 2 Corinthians, and one of the issues that surfaces occasionally is reference to Paul's speaking ability.
The situation in Corinth when Paul was writing 2 Corinthians: There are some new Christian teachers in Corinth (whom Paul labels "false") who are all the rage, for they speak well, apparently. And Paul is seemingly disparaged by these teachers and consequently by at least some of the believers for his lack of ability when it comes to public speaking. For example, he is unimpressive in person "and his speaking amounts to nothing" (10:10). Paul readily admits that he is not "a trained speaker" (11:6), but he refuses to yield ground to the polished professionals--he is not "in the least inferior to the 'super-apostles'" (12:11). Neither is anything he teaches less than the truth (cf. 4:2; 6:7; 11:6).
The question that came up in my Bible study was about Paul's speaking ability. Was he that bad? My response was that it could be he wasn't that good of a public speaker, but the truth of the gospel came out, and people were saved. (Wasn't Spurgeon saved under the ministry of a preacher lacking in eloquence but who nonetheless held aloft Scripture truth?) But (I told my class) I leaned more toward the idea that Paul was a good speaker--his sermons recorded in Acts seem persuasive and able--but that he didn't abide by the standards of rhetoric in his day.
What I learned from Thiselton is that there were two forms of rhetoric in Paul's day. There was the classical tradition, and there was the Sophist form, prevalent in provincial centers and especially in Corinth. The classical tradition (Aristotle, Seneca, Cicero, Quintilian) focused on persuasion and the effective communication of truth, whereas the Sophist tradition was more about sounding good; truth was not the critical element. Seneca complained of the Sophist style that often the goal was "to win approval for yourself, rather than for the case."
No wonder Paul could not and would not accommodate himself to such a style as wowed Corinth. His was a concern for the truth and for Christ as opposed to winning approval and acclaim for himself, for, "We do not preach ourselves but Jesus Christ as Lord and ourselves as your servants for Jesus' sake" (4:5).