11 God gave Paul the power to perform unusual miracles. 12 When handkerchiefs or aprons that had merely touched his skin were placed on sick people, they were healed of their diseases, and evil spirits were expelled.
13 A group of Jews was traveling from town to town casting out evil spirits. They tried to use the name of the Lord Jesus in their incantation, saying, "I command you in the name of Jesus, whom Paul preaches, to come out!" 14 Seven sons of Sceva, a leading priest, were doing this. 15 But one time when they tried it, the evil spirit replied, "I know Jesus, and I know Paul, but who are you?" 16 Then the man with the evil spirit leaped on them, overpowered them, and attacked them with such violence that they fled from the house, naked and battered. 17 The story of what happened spread quickly all through Ephesus, to Jews and Greeks alike. A solemn fear descended on the city, and the name of the Lord Jesus was greatly honored. 18 Many who became believers confessed their sinful practices. 19 A number of them who had been practicing sorcery brought their incantation books and burned them at a public bonfire. The value of the books was several million dollars. 20 So the message about the Lord spread widely and had a powerful effect.
Matthew Henry's Commentary on Acts 19:11-20
Commentary on Acts 19:8-12
(Read Acts 19:8-12)
When arguments and persuasions only harden men in unbelief and blasphemy, we must separate ourselves and others from such unholy company. God was pleased to confirm the teaching of these holy men of old, that if their hearers believed them not, they might believe the works.
Commentary on Acts 19:13-20
(Read Acts 19:13-20)
It was common, especially among the Jews, for persons to profess or to try to cast out evil spirits. If we resist the devil by faith in Christ, he will flee from us; but if we think to resist him by the using of Christ's name, or his works, as a spell or charm, Satan will prevail against us. Where there is true sorrow for sin, there will be free confession of sin to God in every prayer and to man whom we have offended, when the case requires it. Surely if the word of God prevailed among us, many lewd, infidel, and wicked books would be burned by their possessors. Will not these Ephesian converts rise up in judgement against professors, who traffic in such works for the sake of gain, or allow themselves to possess them? If we desire to be in earnest in the great work of salvation, every pursuit and enjoyment must be given up which hinders the effect of the gospel upon the mind, or loosens its hold upon the heart.