Acts 16:6

And they went through the region of Phrygia and Galatia, having been forbidden of the Holy Spirit to speak the word in Asia.

THE MACEDONIAN CALL

Phrygia and Galatia ... The exact boundaries of these cannot certainly be known, due to the dual usage of the term "Galatia," the view preferred here being that the churches of south Galatia (the larger Roman province) which Paul had founded on the first tour were again revisited in this. It is only fair, however, to note that Lightfoot and many others suppose that the more restricted meaning of "Galatia" as applied to the country north of those churches was at this point visited and evangelized by Paul.

Here they suppose Paul was delayed by illness (Galatians 4:13), and seized the opportunity of preaching and founding numerous Celtic or Gallic churches which are nowhere mentioned in the book of Acts.[1]

Forbidden of the Holy Spirit to speak the word in Asia ... The word "Asia" here does not refer to the continent, but to the Roman province of that name which lay west of the cities evangelized in south Galatia on the first tour. In it were the great city of Ephesus, and also the other cities mentioned in Revelation: Sardis, Smyrna, Philadelphia, Laodicea, Pergamum, and Thyatira. It was only natural that Paul should have planned to evangelize those places, but the Holy Spirit forbade him.

How did this prohibition come to Paul? Was it some subjective impression borne inward upon his soul by God's Spirit, or did it come in the direct words of some recognized prophet in the early church? In the light of Luke's own explanation in Acts 20:23 and Acts 21:10, the latter possibility seems the correct one.