What does 1 Corinthians 16:9 mean?
Paul has been describing his travel plans to the Corinthians, including his plan to come and spend some time with them within the year before winter sets in. He does not plan to leave Ephesus, however, until Pentecost—either the literal date or the season. Now he explains why."A wide door for effective work has opened to [Paul]" in Ephesus. He often uses the analogy of a door when describing the openness of a region to hearing the gospel and trusting in Christ (2 Corinthians 2:12; Colossians 4:3; Acts 14:27). However, there are also many enemies opposed to the gospel at the same time. In fact, throughout Paul's ministry, great opposition to the gospel flared up in response to great interest in the gospel, often placing him in danger as more and more people came to faith in Christ.
Once again, Paul demonstrates in this statement that he views opposition to the gospel as part of the evidence that it is being effective. His instinct is not to run but to double down on his ministry when things begin to get heated.