Acts 16:6-10 (New King James Version) 

"Now when they had gone through Phrygia and the region of Galatia, they were forbidden by the Holy Spirit to preach the word in [a]Asia. After they had come to Mysia, they tried to go into Bithynia, but the [b]Spirit did not permit them. And they passing by Mysia came down to Troas. And a vision appeared to Paul in the night; There stood a man of Macedonia, and prayed him, saying, Come over into Macedonia, and help us. And after he had seen the vision, immediately we endeavoured to go into Macedonia, assuredly gathering that the Lord had called us for to preach the gospel unto them."