The following is taken from a book by James Montgomery Boice, Acts: An Expositional Commentary (Grand Rapids, MI: Baker Books, 1997), 319–326.
Greenway points out that Paul had certain basic goals.
To preach a message, one that demanded personal repentance and conversion.
Sometimes when people think of advancing into new areas, they think of changing their message to accommodate the new audience or situation. Are we going into the cities? If so, we think we will have to say what city people want to hear. Are we going on television? If we are, we think we imagine that we will have to do what the television audience has been programmed to expect.
The apostle Paul never changed his message. He taught the nature of sin, the need for repentance, the saving work of God in Christ, and the necessity of conversion. Paul always kept personal repentance and conversion before his mind. We have already seen it in the accounts of these missionary journeys.
To plant churches.
Paul was not just an evangelist who somehow was removed from the task of planting churches. When he went into a new area, church planting was a goal. If he settled in Corinth, he wanted to leave a church in Corinth when he passed on to other cities, and he wanted to leave Corinthians in charge of it.
When we enter an area, we need to spread the gospel, which we can do through books, tracts, radio, television, and other forms of mass communication. Books will explain Christian doctrine. Tracts will popularize the gospel and attract new people. Radio and television will break new ground. But proclamation alone is not enough.
It must be followed by actualization. There must be living communities of believers present, so people living in the cities will be able to look at them and say, “Not only are these Christians speaking the gospel to us, but they are living it too.”
I notice that much of Paul’s work was done in what we today would call “house churches.”
Sometimes, as in Ephesus, Paul had a formal lecture hall. What he did there would correspond closely to what we do in our churches on Sundays. We use them as places to teach. Teaching was an important part of Paul’s strategy. But where he succeeded, churches were established, and these it would seem were in the homes of the people. So here and there throughout these cities were little communities of believers who met together regularly to worship God and model the gospel by their obedience to Jesus Christ.
To use his churches as bases for reaching out into adjoining areas.
Once Paul had established churches he also drew them into his missionary strategy by using them as bases for the extension of the gospel into the surrounding neighborhoods and the world.