What does Acts 19:17 mean?

Ephesus was so well known for witchcraft that the phrase "Ephesian writings" refers to inscribed magical spells. The city also had an infestation of demons, likely drawn by the humans who desired interaction with supernatural power. The demons, in turn, attracted Jewish exorcists. The Roman Empire was so inundated with gods and idols that people sometimes looked to the east for more esoteric, less banal spirituality. Judaism, with its invisible God, often drew interest, and Jewish magicians, looking to make money, took advantage.

So it is that Paul's ministry might not have seemed so unusual except that it is incredibly effective. He not only heals and expels demons, but also cloth he has touched heals and expels demons. The Jewish magicians note he uses the name of "Jesus" and add the name to their repertoire of magical incantations (Acts 19:11–12).

It may have been effective for some demons, but when seven sons of a Jewish high priest try to exorcise a powerful demon "by the Jesus whom Paul proclaims," the demon acknowledges it knows Jesus and Paul but not them. He then beats them until they flee from the house naked (Acts 19:13–16).

The Ephesians suddenly realize that words hold no power but "Jesus whom Paul proclaims" does. They worship Jesus, repent from their witchcraft, and burn their spell books (Acts 19:18–19).