What does 2 Corinthians 4:2 mean?

Paul's bottom line about his ministry is this: What you see is what you get. He and his friends understand their purpose, given by God, to carry the gospel of faith in Christ to the world. They refuse to give up even when things get difficult (2 Corinthians 4:1), and they refuse to cut corners to make the work easier.

It seems there were accusations Paul was being false about some things. Perhaps he was accused even of being a false apostle. He declares his innocence in this verse. He and his co-workers have flatly refused to ever use disgraceful or deceptive means to achieve anything. They are resolved to never be sneaky in any way or about anything. They certainly would never tamper with God's Word by watering it down or manipulating it for their own advantage or by adding to it. They understand their work to be given to them by God, and they know they are responsible to Him to get it right.

That's why Paul now says confidently, everyone is welcome to look at how they conduct themselves and what they say. Critics can see for themselves if the apostle and his friends are being truthful. They speak openly, in full view of all, and all are welcome to search in God's sight to see if they can find any hidden thing going on with Paul and his co-workers. Paul is confident that nobody will, because he has nothing to hide from anyone.