What does Acts 16:10 mean?

During Paul and Barnabas' first missionary journey, they traveled to the island of Cyprus. After this, they went up into central modern-day Asia Minor in the province of Galatia. On Paul's second journey, this time with Silas, they go overland from Syrian Antioch to visit the same churches in Galatia. In Lystra, they pick up Timothy, a young Jewish Christian who quickly becomes Paul's "true child in the faith" (1 Timothy 1:2).

From Galatia, the team has several options. They can go west into the province of Asia, home to several large cities. Or they can move north to Bithynia where their evangelism would reach those who sail the Black Sea. But the Holy Spirit pulls them even farther west. They reach the port city of Troas on the westernmost point of Asia Minor where Paul has a vision of a man asking him to come to Macedonia, on the northern section of the Greek peninsula, to "help" the people there (Acts 16:9). Paul's team immediately knows that "help" means sharing Jesus' offer of reconciliation with God.

This verse includes a small change that is easy to overlook. For the first time in the book of Acts, the pronoun changes from "they" to "we." Luke, the "beloved physician" (Colossians 4:14), has finally joined the group. He stays until Paul, Silas, and Timothy leave Philippi for Berea (Acts 16:40) and eventually meets up with Paul again in Macedonia when Paul is on the return trip from his third missionary journey (Acts 20:5). Luke stays either with or near Paul during his arrest in Jerusalem, imprisonment in Caesarea Maritima, sea voyage to Rome, and Paul's house-arrest there (2 Timothy 4:11). He is the only known Gentile writer of the New Testament, and his letters to Theophilus—the gospel of Luke and the book of Acts—comprise over a quarter of the New Testament.