[Paul, Silas, and Timothy] went through the region of Phrygia and Galatia, having been prevented by the Holy Spirit from speaking the word in the province of Asia. When they came to Mysia, they attempted to go into Bithynia, but the Spirit of Jesus did not allow them to do this, so they passed through Mysia and went down to Troas. A vision appeared to Paul during the night: A Macedonian man was standing there urging him, "Come over to Macedonia and help us!" After Paul saw the vision, we attempted immediately to go over to Macedonia, concluding that God had called us to proclaim the good news to them [Acts 16:6-10].For some time I have felt an unusual attraction to this passage in Acts. The apostles Paul and Barnabas wanted to leave Antioch in Syria to check on the churches they had planted on their previous missionary journey. Because they couldn't agree about whether to bring along Barnabas's cousin John Mark, who had quit early on their last trip, they split up. Barnabas took Mark to Barnabas's old stomping grounds of Cyprus while Paul took Silas to check on the churches in the southern reaches of the Roman province of Galatia, which took them through Paul's native region of Cilicia. (I wish I could find the perfect map to show you all this, but I can't. Here are three maps that, put together, help you visualize where Paul traveled:  a map of the regions of ancient Anatolia [modern western and central Turkey] with Greek placenames;  a map of the Roman Empire in A.D. 125, about 75 years after Paul's journey; and  a modern satellite view of the northeastern Mediterranean showing the location of cities mentioned in the New Testament.)
After Paul and Silas checked on the southern Galatian churches (and recruited Timothy in Derbe) they began looking for the next thing to do. It was only logical to begin preaching Christ in the Roman province of Asia (consisting of roughly the western third of modern Turkey), which included most of Phrygia and Mysia among other places. It was the next unreached ring beyond where Paul and the gospel had already gone. But the Holy Spirit wouldn't let them. Then they wanted to go north into Bithynia on the southwestern coast of the Black Sea, but the Spirit wouldn't let them go there either, so they wandered down to Troas, still stuck in Asia with nothing to do.
How confusing this must have been! How many cities and villages did Paul and his comrades walk through, watching Jews reading the Law and ignorantly waiting for their Messiah who had already come, watching Gentiles worshiping statues of false gods and the invisible demons behind them and committing detestably immoral acts, and yet the Spirit would not let them do anything. How they hoped to go to new places to preach the gospel, and the Lord wouldn't let them! How could this be? What did God want? Why wasn't this going as smoothly and easily as when Paul and Barnabas just hopped on a ship, sailed to Cyprus, and started preaching immediately?
The answer comes when Paul sees the vision of the man of Macedonia in what is today northern Greece calling for help. This is what God had denied the apostles for, so that they could go even further than they had imagined to proclaim the good news, two provinces beyond where Paul had planted churches last.
But what may easily be overlooked is that even as God denied Paul what Paul desired and must have believed to be logical—preaching the word in the province of Asia—he was silently working in multiple ways to see that Paul's dream would be fulfilled.
First, in Troas Paul and the gang found a new traveling companion—the author of Acts, whom we believe to be Luke. We know this because in verse 10 he says that "we" went over to Macedonia. This may mean that Paul disobeyed the Spirit and spoke the word in Troas, and Luke was saved there and joined up with them. But it seems more likely, especially because of the maturity they must have found in Luke, that he was already a believer in Jesus when they met him. We know that there were Jews from the province of Asia at Pentecost who believed in the Lord that day. Luke may have been one of them who then returned home or perhaps had heard the word from one who did. (Luke is commonly considered the only Gentile author of the New Testament, but I think he was more likely a Hellenized Jew. I have my reasons, but that's another topic.) In any case, God was already at work in this "unreached" region before Paul passed through.
Second, once Paul and his crew arrived in the Macedonian city of Philippi, their first convert was a Gentile God-fearer (i.e., worshiper of Israel's God who was not a full convert to Judaism) named Lydia. But "Lydia" almost certainly was not her real name but her local nickname to the folks in Philippi, because Lydia had moved there from her hometown of Thyatira, a city in the province of Asia on the border between the regions of Mysia and Lydia. (I once heard of a guy nicknamed "Bama" because he came from Alabama; it's a similar thing.) Even though Paul had not presented the gospel to the people of Asia in Asia, God gave him the opportunity to bring one of them to salvation in a completely different place.
Third, as Paul continued his trip, he ended up in the city of Corinth in southern Greece (province of Achaia), where he met two other Jewish believers in Jesus who had recently relocated there from Rome, Aquila and Priscilla. After a year and a half, the three of them (with Silas and Timothy) sailed east for Ephesus, the most prominent city in Asia. But now that Paul finally had a chance to proclaim the word there, he only stayed there briefly, leaving Priscilla and Aquila to do most of the work. Again, even though it wasn't in God's plan for Paul to speak the word extensively in Asia as he wished, God still planned to spread his kingdom through the work of others that Paul had equipped.
Fourth, a few years later, it was finally Paul's turn. On his third missionary journey Paul once again passed through the cities where he had planted churches with Barnabas, but this time he went straight for Ephesus and stayed there for two whole years. During this time God did astonishing acts of supernatural healing through Paul such that he was renowned by humans and demons alike. His ministry was so effective that through him and the believers that he equipped that the entire province of Asia heard the word of the Lord. That's right: the whole thing.
So Paul got his wish many times beyond what he expected. His desire was to proclaim the word to the people of Asia, the logical next step after his work in Galatia. Inexplicably, the Spirit told him no for some time. But meanwhile God had already placed some initial believers there, gave Paul the chance to do what he wished in an unexpected setting, enabled Paul to equip others to pioneer the work, and finally gave Paul his desire having prepared the ground so thoroughly that it was probably the most Spirit-empowered and prosperous period of his entire apostolic career.
Paul's example hit home to me recently. I had applied with my church for a grant that would have enabled a remarkable learning and growing opportunity for me and for all of us. We felt sure that applying was the right thing to do, but months later we were disappointed—we were not selected. It seemed like an opportunity that would never come again; the timing would have been perfect, and now the moment was lost. But coming in the mail at about the same time as the rejection letter and sitting on my desk unopened for some time was an invitation to a very different but equally remarkable opportunity that I never saw coming. In addition to being as enthusiastic and grateful as Paul and his companions were to receive the call to Macedonia, I feel certain that my Macedonia will somehow lead back to my Asia in ways I never would have imagined and that once I get there I will be more useful for the kingdom than I ever could have been otherwise.
If you are experiencing a similar disappointment and confusion to what Paul must have experienced as he was wandering aimlessly through Asia to settle at the dead end of Troas, I hope that his example is an encouraging lesson to you. When God frustrates our holy desire to serve him in the way that makes perfect sense, he has a reason. Whether through one or all of the means he gave Paul, he will give you the desire of your heart.