In 2 Corinthians 2, we read about the restoration of the brother whom Paul had disciplined earlier (1 Corinthians 5). Now Paul says, " You should receive him back now" (2 Cor.2:6-8). That brother had learnt his lesson when everyone in the church avoided him - and he saw how dark it was out in the world. He had set matters right and given up his sinful ways. But now he was discouraged and depressed, sitting alone at home. Paul asked the church to restore him.
The purpose of all discipline is to bring a brother back into fellowship with God and the church. A father disciplines his child, not to drive him out of the house, but to make him a better son. If the son is a grown man and rebellious, then the father may tell him to leave his house. But even in such a case, once the son has learnt his lesson (like the prodigal son), the father will welcome him back home. This is what Paul is saying here. Paul says, "If you forgive him anything, I also forgive" (2:10). And then, there is a word for all of us: " We must forgive others so that no advantage is taken of us by Satan" (2:11). It is extremely dangerous to live without having forgiven someone.
If someone has done you harm and you don't forgive him, Satan can destroy your life. The person who harmed you may repent later and enter God's kingdom. But you, who never did him any wrong, may go to hell, because you didn't forgive him. That looks unrighteous - that the person who did the wrong goes to heaven and you who suffered the wrong goes to hell. But it can happen if he repents and you don't forgive him. Jesus said, " If you don't forgive someone, My heavenly Father will not forgive you" (Matthew 6:15). If your heavenly Father does not forgive you, how can you enter heaven? So if you die without forgiving anyone, as per Jesus' word here, you will go to hell, irrespective of how long you were a believer before that. So, we must develop the habit of forgiving others immediately, no matter what harm they did to us. Otherwise Satan will get an advantage over us.
Paul says, "We are not ignorant of his schemes" (2:11). Satan is always trying to trip us up. Why do you think Satan constantly reminds you of the evil things that others have done to you in the past? Do you think he is sympathising with you? No. He already got a hold of that other person to harm you. Now he wants to get a hold of you as well! Don't be ignorant of his schemes. Forgive everyone.
Once a brother came to me and complained that someone had done a number of evil things to him. I asked him, "Has he crucified you yet?" He said, "No." So I told him, "Then you have a long way yet to go in following Jesus, because He forgave even those who crucified Him."
Paul's testimony in 2:14 - "Thanks be to God who always leads us in His triumph in Christ" - came to me as a challenge many years ago - especially the word 'always.' I wondered if that was possible. Paul experienced constant triumph - and thanked God for giving him such a life. He didn't say that he was walking in triumph by his own power. No. He said that it was God Who led him in triumph always. So Paul was an overcomer. He wasn't perfect. He did slip up occasionally. Towards the end of his life he once got angry and shouted at the high priest (Acts 23:3). But he humbled himself and asked for forgiveness, as soon as he was aware of his sin. Thus his fellowship with God was restored immediately - and he lived an overcoming life constantly.