For all of the action in the book of Acts, it has an oddly unsatisfying ending: “Paul lived there [in Rome] two whole years at his own expense, and welcomed all who came to him, proclaiming the kingdom of God and teaching about the Lord Jesus Christ with all boldness and without hindrance” (Acts 28:30–31).
Haven’t the last 8 chapters been all about Paul getting to stand before Caesar? Does he get there? And what happens then? We don’t know. And didn’t Paul want to go on from Rome to preach the gospel in Spain afterward? Did that happen? We don’t know. Acts doesn’t tell us.
Acts ends in a cliff-hanger. Luke doesn’t tell us what happens to Paul and his aspirations. Why? Because Acts isn’t about Paul or his dreams. It’s about the Spirit and the gospel. Paul would eventually die, beheaded by the Emperor Nero. But here we are—the church—2,000 years later, proving to Nero that you can kill and imprison Paul, but you can’t stop the gospel he preached.