Why did Paul say he wrote to the Corinthians in 2 Corinthians 2:9?

Les teaches that in 2 Corinthians 2:9 Paul says, "For to this end did I also write," referring to taking care of the immoral situation and getting the man straightened out. Paul then states the further reason: "that I might show the proof of you, whether you be obedient in all things." Les explains this as a test of whether the Corinthians would respond to the immorality or ignore it. They did respond, and the majority had evidently voted to deal with the individual and bring him to forgiveness and restoration. Les also notes that Paul had no power to forgive sin himself, but in the name of Christ he could agree with their restoration of the individual. The purpose of restoring the failed man was to keep Satan from getting the upper hand, for Paul says we are not ignorant of Satan's devices.