How the word of God grows and prevails
And many that believed came, and confessed, and shewed their deeds. Many of them also which used curious arts brought their books together, and burned them before all men: and they counted the price of them, and found it fifty thousand pieces of silver. So mightily grew the word of God and prevailed. Acts 19:18-20
Here see the true effects of saving faith: confession of sin and repentance. The repentance is shown in the fact that those who practiced the magic arts ("curious arts") took their books and burned them. They did this voluntarily and willingly. It was a sign that they had departed from the old life they had practiced. They wanted no more to do with it, and they wanted nothing more to do with those books that instructed them in those demonic practices of incantations and spells.
They did this, even though such books were apparently very valuable. The price of the books that were burned was "fifty thousand pieces of silver," a piece of silver probably being a laborer's daily wage. That's a lot of money. Repentance and faith, in other words, will part with sin no matter how much we loved it before. For the love of God will brook no competitors. You will either serve God or mammon, but not both (Mt. 6:24).
In this way the word of God grows mightily and prevails. The church doesn't just grow when its numbers increase; it grows when sin is parted with. Let us pray that this becomes more and more a reality in our own lives. And let us pray that God will do such a mighty work in our city that his word will grow and prevail against all the arts of Satan.