What does 2 Corinthians 5:11 mean?

Paul writes in this verse that he knows "the fear of the Lord." This is not a reference to terror or anxiety. He does not mean that he fears eternal damnation. Paul teaches that salvation from sin and hell is a gift given freely by God to all who trust in Christ. It is not obtained by doing good works (Ephesians 2:8–9). The "fear" here is used in the ancient sense of respectful awareness, the way mature adults have a "healthy respect [fear]" of things like fire or electricity.

Paul described in the previous verse why he lives in "fear of the Lord." He is aware that once this life is over, every heaven-bound believer will have his or her works judged by Christ. All we have done in our bodies on this side of eternity will be shown to be worthwhile or worthless, in service of Christ or serving only ourselves. Each will be rewarded or reprimanded based on his or her choices. Paul's reverent awe for Christ, whom he represents as an apostle, motivated him to keep carrying the gospel of salvation to more and more people in order to receive Christ's commendation at that judgment.

This brings the theme of 2 Corinthians back to a defense of Paul and his co-workers. They are genuine in their work for Christ, a fact apparently being challenged in Corinth. Paul writes that God knows what they are, meaning that God knows their mission, their motivation, and the fruit that has come from that. Paul adds that he hopes his readers know, in their conscience, what he and his co-workers are, as well. He hopes the Corinthians are fully convinced about the genuineness of the work Paul and those with him have done among them.