1. You are our letter, written by God (1-3)
God's word is a letter from God to us; also, God's Spirit applies the word to our lives by writing it on our hearts. We then become letters from Christ to the world. The world should see the image of Jesus reflected in our lives. Paul did not have to defend himself as a servant of God; the Christians in Corinth who had been changed by the Spirit of God and the gospel Paul preached were evidence that God was at work in his ministry.
2. Ministers of the new covenant (4-6)
God worked in and through Paul to make him competent as a minister of the new covenant. The new covenant, sealed by Jesus' blood, is God's promise to forgive sinners who repent and believe in Jesus, and his promise to give them his Holy Spirit. The Spirit of God gives believers new birth into the family of God, and into a living hope in the heavenly kingdom.
Application: Lord, give me your Spirit; write your word on my heart and in my life.
One Word: A letter written on the heart