What does 2 Corinthians 6:8 mean?

This passage provides a long list of evidences for the integrity of Paul's ministry. He has listed terrible things endured by himself and his co-workers for Christ's sake. He has listed positive qualities they have shown and evidence of God's power through them.

Now he returns to describing how they have been treated in their ministry. He wants his readers to see that they have kept going even through these things. They have experienced both honor and dishonor in representing Christ. They have been both slandered and praised. Whatever Paul's detractors in Corinth were saying about him had likely been said before. Paul did not live for the praise of other people, but he wanted his readers to know that he received it for his work in the ministry, along with insults and lies.

In fact, Paul adds that they had been treated as impostors. It's possible that this is what was happening in Corinth, with some suggesting Paul and his team were false apostles. Paul addressed those accusations specifically in 2 Corinthians 3:1–3, asking the Corinthians to look at their own conversions to faith in Christ to remember that his work as an apostle among them was "true."