Paul had no reason to commend himself through letters. His ministry spoke for itself and the Corinthians were evidence of that (2 Corinthians 3).
Unlike the false teachers, who wanted to put them under the law, Paul’s teaching revealed the glory of the gospel of grace (V9) which was transforming them into the image of Christ (V18).
The gospel is a ministry of mercy (2 Corinthians 4) and light revealing salvation through Christ and not the law (V4). Therefore Paul did not have to preach himself but Christ only. Paul and his companions were bondservants to them bringing this message (V5).
Though trials may face us from every direction, in Christ we are not crushed, struck down or destroyed. Even if killed, we have the promise of being raised up as Jesus was raised (V14). It’s easy to get our eyes on our troubles, but we are not to look at the things seen, but at the things unseen. What we see is temporary; the unseen is eternal (V18).
In Christ alone we have assurance of the resurrection (2 Corinthians 5) and Christ, who is God, is preparing us for this and has given us the Spirit as a guarantee (V5).
We are to walk by faith not by sight (V7). Since there will be a judgment we should be reconciled to God. This is the message Paul continued to bring that we should no longer live for ourselves but for Him who died for us and rose again (V15).
In Christ we are new creatures; the old ways must pass away, and we must live in newness of life (V17) because our sins have been forgiven through Christ who became sin for us, that we might become the righteousness of God in Him (V21).
The Bible Blog 