Matthew Henry on 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.