Summary: Too often as Christians we take short cuts to maturity. In reality the only way to become complete is to let the Lord take you through difficulty and make you seem to "fail." In the process He builds life and a character in you that will lead you into His
We all have a decision to make. After we become a disciple of Jesus Christ the culture around us, our own brokenness, and an invisible enemy—will all try to mitigate the work that the Holy Spirit is doing inside of us: transforming us into a new character. The decision we have to make is how much we will cooperate with that metamorphosis. Your mind will justify anything you let it. That’s why we get ourselves into trouble and think we are doing okay! The Corinthians had let “this age” thinking permeate so deeply that they were biting and scratching at each other and attacking the Apostle Paul and all the while thinking that the con-men they had embraced were the real deal—when in fact they were emissaries of Satan. So Paul faces them off at the end of 2 Corinthians with the choice—recognize the flesh ruling and give back ownership of their lives to Jesus and their allegiance to the guy who led them to Christ: Paul. Let’s see how that plays out for them, and talk a bit about how it works in our lives.
Paul quotes Deuteronomy 19:15 (quickview)  here. Commentators have suggested two interpretations: one is that Paul was coming to the Corinthians as a judge to set matters in order in a disorderly church. Others suggest he is counting visits as witnesses. This third visit is like the third witness against the Corinthians. It’s likely that both interpretations are correct. Like in Matthew 18 (quickview) , Jesus suggests the use of two or three witnesses when confronting a sinning brother or sister, but also three different levels: personally, before witnesses, and before the church.
I guess for us the word is: when it comes to discipline in the church, make sure you don’t do it alone, and that you allow for plenty of time for the person to respond.
This supports the “three times” interpretation of verse 1. Paul warned in person twice, and now is warning again while absent that when he comes he will deal with the sin in the church. “Not be lenient” in the Greek basically suggests that Paul will not hold back. In essence the Corinthians had been given time and encouragement to let go of sin and turn away from the false teachers who preached “this age” thinking. The time for warnings was over. Time itself was up. No more “meek and mild” Paul.
The idea of progressive discipline seems to be a Scriptural pattern. Pharaoh got warning after warning before God hardened his heart and killed the firstborn. Saul got several warnings from Samuel before God had had enough. The Pharisees and religious leaders in Israel got warned many times by Jesus but there came a time when they would bear responsibility for their choice to reject Jesus.
All the more reason to listen to the voice of the Holy Spirit and the Scriptures speaking to you to repent.
Galatians 6:7-9 (quickview)  Do not be deceived, God is not mocked; for whatever a man sows, that he will also reap. 8 For he who sows to his flesh will of the flesh reap corruption, but he who sows to the Spirit will of the Spirit reap everlasting life. NKJV