One of the criticisms directed against Paul was that he was all bluff – that he was weak. That he wrote strongly when away but was weak when he was amongst them. Well, Paul is writing that when he comes, he will not exercise the same amount of restraint. After-all he is an apostle of the Lord Jesus. These are strong words from Paul. The Corinthians had mistaken delay, gentleness, even meekness for weakness. Paul on the other hand had exercised Christian patience. Part of the fruit of the Spirit is patience and Paul has exercised that aspect of Christian character (Chapter 10:1, by the meekness and gentleness of Christ). Still there was an end to his patience and the Corinthians would soon feel that if they failed to discipline themselves. When it comes to disciplining children, you can cut them some slack, but if you never discipline, the lack of discipline will be seen as a licence to be naughty, to cause grief.
2 Timothy 3: 16-17
All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.