Acts is the book that reveals the power of the church. Therefore, when a church begins to dwindle, lose its power, and turn dull and drab in its witness, it needs desperately to get back into the spirit, expectation, knowledge and teaching of the book of Acts. In this book, the principles of the exchanged life — "Not I, but Christ" — is dramatically unfolded.
If the book of Acts were taken out of our New Testament, we would never understand the rest of it. It would be like a child with his front tooth missing. When you close the record of the gospels, you see nothing but a handful of Jews in the city of Jerusalem, the center of Jewish life, talking together about a kingdom for Israel.
When you open the book of Romans, on the other side of Acts, you discover that a man whose name is never mentioned in the gospels is writing to a group of Christians in Rome — of all places, the center of Gentile culture — and he is talking about pushing out to the very ends of the earth. Obviously, something has happened in between. How did this tremendous change take place? What happened to make the gospel burst out of its confines in Judaism and the city of Jerusalem and reach out in one generation's time to all the limits of the then-known world?