In Acts 18:1-17, Luke briefly narrates the account of Paul’s first visit to Corinth that resulted in the founding of a church, as well as persecution from his opposition.
Like similar accounts of his ministry resulting in opposition (Acts 13:50-51; 14:5-7, 19-20; 16:22-40; 17:5-10a, 13-14), Paul intended to leave Corinth and move onto the next place.
But Jesus came to Paul in a vision and said, “Do not be afraid; keep on speaking, do not be silent. For I am with you, and no one is going to attack and harm you…” (Acts 18:9-10). And Paul stayed for 18 months (Acts 18:11).
Jesus made a unique promise to Paul: “no one is going to attack and harm you.” And this promise seems to apply only in that unique setting in Corinth, for Paul was harmed before arriving in Corinth (for example, in Philippi in Acts 16:22-24). And according to church history, Paul was martyred in the mid-60s under Nero’s reign.
We must be careful so as to avoid a serious error when reading Acts 18:10. That error would be thinking, “Jesus promised Paul he wouldn’t be harmed, so we can claim that promise when we are engaging in missions.”
The reason such an interpretation would be a mistake is based on Paul’s teaching in other churches that conveys the exact opposite: “We must go through many hardships to enter the kingdom of God” (Acts 14:22). Elsewhere he said, “Everyone who wants to live a godly life in Christ Jesus will be persecuted” (2 Tim 3:12). And the Lord told Ananias concerning Paul, “I will show him how much he must suffer for my name” (Acts 9:16).
So it is a mistake to interpret Jesus’ promise to Paul as a promise to every believer. Instead of gospel-work being comfortable and easy, the opposite is promised to us in the New Testament: we will face persecution and the world will hate us. That is what we’ve been promised.
Paul not experiencing physical persecution in Corinth seemed to be an exception to the rule. Read Paul’s own recollections of what he endured while on mission for God (2 Cor 6:4-10; 11:23-27).