What does Acts 21:2 mean?

Paul, Luke, and several others (Acts 20:4) are on their way to Jerusalem. Paul's companions are going because their home churches—in Ephesus, Troas, Thessalonica, Philippi, and Berea—have collected support for the church in Jerusalem (Romans 15:26). Paul is going so he can continue to serve God in his own way; in this case, that will include being arrested.

They leave Miletus, a port on the southwest corner of modern-day Turkey, and round the peninsula until they reach Patara on the island of Rhodes. From here, it's straight to Tyre on the coast of Phoenicia, north of Galilee. They will spend a week in Tyre while the ship unloads before sailing south to Ptolemais and Caesarea Maritima. At Caesarea, they will head inland to Jerusalem.

On their way to Phoenicia, the ship will pass the southern coast of the island of Cyprus. Cyprus is the original home of Barnabas, and the first place Barnabas and Paul went after the elders at Syrian Antioch commissioned them to bring Jesus' story to the Gentiles (Acts 13:4).

Phoenicia is a district along the coastline of Syria. It is flanked by the Mediterranean on the west and a rugged mountain range on the east. It takes up much of the same territory as modern-day Lebanon while spilling north into Syria and south into Israel. The ship will land in Tyre, an ancient seaport first mentioned in the book of Joshua. The king of Tyre gave King David supplies for his royal house (2 Samuel 5:11).

Despite their proximity to Cyprus, they do not stop to visit the proconsul who came to faith in Jesus (Acts 13:12). Nor do they go north to Paul's home church in Syrian Antioch. The Holy Spirit compels Paul to reach Jerusalem by Pentecost (Acts 20:16). Even though Paul knows he will face arrest and persecution, he knows he must go.