Acts 16:16-20
Acts 16:16 (KJB)
And it came to pass, as we went to prayer, a certain damsel possessed with a spirit of divination met us, which brought her masters much gain by soothsaying:
Soothsaying - Fortune telling
As soon as Paul had a great time meeting with the new believers, it is time for Satan to attack. As they were going to prayer, they had met a woman who had been possessed by a devil. In the Greek, her “spirit of divination” was a “spirit of ventriloquism.” A devil had possessed her and was using her body to foretell events and speak through her. Whenever we see a ventriloquist speaking through a dummy, it is exactly what the devil was doing through this woman or anyone else who has ever been possessed by a devil. The dummy speaks with the ventriloquists voice because it cannot fight back since it is a dead object. Those who are devil possessed are also spiritually dead and the devil will use them as he sees fit until the person becomes saved and then the devil has to flee because the Holy Spirit will cause him to flee. This woman in this verse was being used not only by the devil but by her masters who used her to make much money. They cared nothing for their souls or hers, only profit. She may have been a slave girl.
Acts 16:17 (KJB)
The same followed Paul and us, and cried, saying, These men are the servants of the most high God, which show unto us the way of salvation.
(Luke 4:34 KJV) Saying, Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art; the Holy One of God.  Just as the Lord Jesus Christ would not receive the testimony of the devils from hell and neither would Paul. The devil which possessed the girl, knew exactly who Paul was and in their presence the devil was preaching the way of salvation and Paul would not accept a devil to preach salvation. The devil may have done that in a mocking tone nevertheless, preaching was to be done only by God’s appointed people and not the unbeliever nor the devils. She had followed Paul wherever they went. Paul also did not accept for another reason because to the Greeks, their high god was Zeus and if she kept on yelling, people would think they were priests of Zeus instead of the true God in Heaven.
Acts 16:18 (KJB)
And this did she many days. But Paul, being grieved, turned and said to the spirit, I command thee in the name of Jesus Christ to come out of her. And he came out the same hour.
She had trailed after Paul for many days and finally when Paul had his fill of this devil filled individual, he became grieved in his heart for her. She might have been yelling in shrieks and cries calling the wrong kind of attention to them. So he finally turns to her and in the name of Jesus Christ, he cast out the demon from the girl. Notice, he did not address the girl but he directly addressed the devil in her and when the name of Jesus Christ is called upon, the devil in her had to go. She was finally free from the devil possession and probably had rest like the Gadarene Demoniac. (Mark 5:15 KJV) And they come to Jesus, and see him that was possessed with the devil, and had the legion, sitting, and clothed, and in his right mind: and they were afraid. Those pig herders probably like the demoniac being by their herds because no one would want to go near them with him there and this girl brought much gain to her owners.
Acts 16:19 (KJB)
And when her masters saw that the hope of their gains was gone, they caught Paul and Silas, and drew them into the marketplace unto the rulers,
Up to this point in the ministry of Paul, most of the persecution had come from the Jews which came from jealousy. This time the persecution would come from the Gentiles. At first, they did not pay any attention to Paul and the owners of the girl did not mind her following after them because it brought attention and probably increased her value to the bosses. However, since the devil was cast out of her, she no longer was of any value to her bosses and their source of gain was now at an end. This caused them to become very angry to the point they seized Paul and Silas and dragged them to the rulers in the marketplace. They didn’t even care that the girl was delivered, all they cared about was their income was now gone and maybe they would now have to go to work.
Acts 16:20 (KJB)
And brought them to the magistrates, saying, These men, being Jews, do exceedingly trouble our city,
The chief magistrates would have been Roman. The accusers did not even tell the magistrates why they were bringing Paul and Silas before them. They conveniently hid the truth. Their accusation was not only that they were trouble makers but it was much more intense that they were “exceedingly” causing trouble. Today it could probably be called mayhem which could send a person to prison. They wanted the magistrates to have the worst possible thoughts about Paul and Silas.