What does 1 Corinthians 4:20 mean?

These are stern words Paul is writing to the Christians in Corinth. He knows that when this letter is read, it will be heard by some among them who have been talking Paul down. He has called them arrogant. They do not believe they need to submit to Paul's instructions to them to change their attitudes and behavior in Christ. Paul has written that some of their arrogance comes from the fact that they don't think Paul is going to come see them in person (1 Corinthians 4:18). Just like those in the modern era who put on a "tough" persona through social media, but would shrink if actually speaking to people in person, Paul says these resistant believers are likely to change their attitudes when Paul actually arrives.

Paul insists that he is coming, if the Lord will allow it. When he comes, he will once more come with the ability to demonstrate God's power through the Holy Spirit (1 Corinthians 2:1–5).

God's kingdom is not about talk, Paul declares. It is about power. That's easy for all of us to forget. So much of our practice of Christianity focuses on words being preached, read, or prayed. All that talk, though, is meaningless without the legitimate power of God behind it (James 2:26). Paul does not want the Corinthians to forget that he did not just introduce them to big ideas that can be captured and manipulated with words. He introduced them to the power of God available only through faith in Christ and the Holy Spirit.