Paul is defending a challenge to his apostleship. What were the signs? They were things the Corinthians could see, the fruits of his ministry. The gospel of the Kingdom of God was preached to them, people were healed, demons cast out, people converted, congregations raised up, and apostles used to clarify doctrine under Christ (as in Acts 15).
John W. Ritenbaugh
Was Mr. Armstrong an Apostle?
The apostle Paul, despite his cautions to Timothy (see II Timothy 2:23; I Timothy 6:3-5), realized at one point that if he did not challenge the foolish challenges of his enemies (concerning his apostolic authority and methods), naïve members of the Corinthian congregation might believe them. His lengthy answer spans II Corinthians 11 and 12.
Obviously, Paul felt extremely uncomfortable about answering these allegations, as is evidenced by his self-effacing reference to himself as a fool, but he also realized that his silence would have tacitly endorsed the charges. Likewise, our Savior, when confronted about His identity and credentials, knew the timing was right to put the gainsaying Pharisees in their place (John 8:52-58).
As one minister said, "If you are going to preach a warning message, you had better be mindful of your exit strategies, or be prepared to die on that hill of battle." There certainly are times when diplomacy fails and silence is no longer appropriate. Our society is replete with foolish teachings, ideas, theories, and misconceptions—both secular and religious—and under the right circumstances, they should be confronted and shown to be false, lest they be accepted as factual.
As maturing Christians, we must learn to discern when it is proper to answer a fool according to his folly (in the manner his foolishness deserves), and when it is a bad idea to answer a fool according to his folly (lowering ourselves to his undignified level). The right exercise of God's Spirit in us, which Paul calls "the mind of Christ" (I Corinthians 2:16), provides the potential to have and use this ability.
David F. Maas
To Answer a Fool—or Not