Also many of those who were now believers came, confessing and divulging their practices.
18. Many which believed. Luke bringeth forth one token of that fear whereof he spake. For they did indeed declare that they were thoroughly touched and moved with the fear of God, who, of their own accord, did confess the faults and offenses of their former life, lest, through their dissimulation, they should nourish the wrath of God within.
The preachers of the gospel were sent forth to carry on a war against Satan, and therein Christ went forth conquering and to conquer. The casting of evil spirits out of those that were possessed was one instance of Christ's victory over Satan; but, to show in how many ways Christ triumphed over that great enemy, we have here in these verses two remarkable instances...
Commenting on Acts 19:13-20
So mightily grew the word of God, and prevailed. Over conjuring books, conjurers themselves, yea, even the devils; the power of God going along with it, many were converted; which is meant by the increase of it, and were delivered from the power of darkness, out of the hands of Satan, and translated into the kingdom of Christ.