What does 2 Corinthians 5:12 mean?

This returns to the issue of those in Corinth who opposed Paul and his co-workers. Critics seem to have been challenging his legitimacy as an apostle of Jesus, perhaps even suggesting that he was being deceptive. Paul insists here that the purpose of his letter is not to re-state the case for himself to the Corinthians. He doesn't feel the need to re-prove his credentials to them. He wrote in the previous verse that he hoped they knew, from experience, that he was a genuine apostle (2 Corinthians 5:11).

Instead of trying to start from scratch with them, Paul has been describing his outlook and his motives. His hope is to remind the Corinthians of his unique role as representing Christ to them. He wants them to boast about him and his co-workers in this sense: Christ cared about us so deeply that He sent Paul to tell us how to receive eternal life through faith in Christ!

Those opposed to Paul among the Corinthians were focused on outward appearances. This may imply they were Jewish religious leaders insisting that the Corinthians "look good" by following the law of Moses. Or it may mean they were describing the outer appearance of Paul's life as one of public defeat instead of public victory. This criticism would strike at the fact that Paul spent so much time suffering and under threat of violence.

Paul wants the believers in Corinth to be able to answer those opposed to him. He wants them to be able to tell Paul's detractors that it is not the outer appearance that matters, but it is what is going on in a person's heart that is truly important. This echoes God's words to the prophet Samuel about choosing a new king for Israel, "Do not look on his appearance or on the height of his stature, because I have rejected him. For the Lord sees not as man sees: man looks on the outward appearance, but the Lord looks on the heart" (1 Samuel 16:7).