Paul, a tentmaker, compares the earthly body to a tent that will one day be taken down. Believers have a building from God, a house not made with hands, eternal in the heavens. They groan in the present body, longing not to be unclothed but further clothed, so that what is mortal may be swallowed up by life. God has prepared them for this and given the Spirit as a down payment. So they walk by faith, not by sight, aiming to please the Lord, knowing that all must appear before the judgment seat of Christ.
The motive of Paul's ministry is the love of Christ, which compels him. He reasons that one has died for all, and therefore all died. Christ died so that those who live would no longer live for themselves but for Him who died and was raised. Paul no longer regards anyone from a merely human point of view. If anyone is in Christ, there is a new creation. The old has passed away; behold, the new has come.
All this is from God, who reconciled believers to Himself through Christ and gave them the ministry of reconciliation. In Christ God was reconciling the world to Himself, not counting trespasses against them. Paul and his co-workers are ambassadors for Christ, as though God were making His appeal through them, and they plead on Christ's behalf: be reconciled to God. The chapter ends with the great exchange. For the sake of His people, God made Him who knew no sin to be sin, so that in Him believers might become the righteousness of God.