During the night Paul had a vision of a man of Macedonia standing and begging him, “Come over to Macedonia and help us

Acts 16:1-15

Paul came to Derbe and then to Lystra, where a disciple named Timothy lived, whose mother was Jewish and a believer but whose father was a Greek. 

As they traveled from town to town, they delivered the decisions reached by the apostles and elders in Jerusalem for the people to obey. So the churches were strengthened in the faith and grew daily in numbers.

but the Spirit of Jesus would not allow them to. So they passed by Mysia and went down to Troas. During the night Paul had a vision of a man of Macedonia standing and begging him, “Come over to Macedonia and help us.” After Paul had seen the vision, we got ready at once to leave for Macedonia, concluding that God had called us to preach the gospel to them.

From Troas, we put out to sea and sailed straight for Samothrace, and the next day we went on to Neapolis. From there we traveled to Philippi, 

On the Sabbath, we went outside the city gate to the river, where we expected to find a place of prayer. We sat down and began to speak to the women who had gathered there. One of those listening was a woman from the city of Thyatira named Lydia, a dealer in purple cloth. She was a worshiper of God. The Lord opened her heart to respond to Paul’s message. 

Why?
On the second trip of missionary, Paul listened to the sound or vision of the Holy Spirit guide his way. So the Gospel was preached to the West side instead of the East Asia area.

Lydia is a woman and she was chosen by the Lord and ready for the coming of Paul, so the members of her household were baptized. This is the work of the Holy Spirit.

Subdue myself before the Lord and the Holy Spirit, and then I can hear the voice of the Holy Spirit.

How to know the vision of the Lord: Relying on the acknowledgment, wisdom, and words of the Lord, after praying and waiting for the vision for one month, if there is no instruction, then we can go on with our plan.  If we have the vision we have to choose one of the targets and give up others. 

How?

To be a good preacher of the Gospel is to listen to the sound or vision of the Holy Spirit. This is why I needed the inspiration of the Holy Spirit.