Kent Hughes in his commentary writes this…
“Whereas chapters 1-9 were directed to the repentant majority of Corinth, chapter 10 – 13 focus on the unrepentant minority. Paul now goes to war against rebellion.” (p. 180). Paul has suffered hit after hit, insult after insult from his detractors. To give you a brief rundown of what they were saying about him. They judged that he had an unimpressive personality, that he lacked rhetorical skills, that he was too meek and mild, even his poverty they saw as a negative. To them Paul didn’t have their ecstatic experiences and visions. They considered his trials and sufferings to be a liability rather than as an asset.