Gevurot Meyruach Hakodesh 16:6-10

And they traveled through the regions of Phrygia and Galatia, having been forbidden by the Ruach Hakodesh to speak the dvar HASHEM in Asia. And having come to the border of Mysia, they were trying to go toward Bithynia, and the Ruach of Moshiach did not permit them. So, passing by Mysia, they came down to Troas. And during the lailah a chazon (vision) appeared to Rav Sha'ul. It was of a certain ish from Macedonia who had been standing and was begging him, saying, Come over to Macedonia and help us. And when Rav Sha'ul saw the chazon, immediately we sought to cross over to Macedonia, concluding that HASHEM had called us to preach the Besuras HaGeulah to them.