Now at Iconium they entered together into the Jewish synagogue and spoke in such a way that a great number of both Jews and Greeks believed.
This very simple account of how the gospel spread on one short stop in Paul's first missionary journey shows how the gospel still works today. Here is what I notice...
First, faithful messengers went with the gospel to people who had not heard it before. In this case, Paul and Barnabus went to Iconium, specifically to the city's synagogue and preached the saving gospel news about Jesus. They obeyed the Spirit's call and simply shared good news.
Secondly, God used their persuasive gifts to bring about a response to the gospel. Luke's authorial observation is that they "spoke in such a way" that the results were clear. That does not mean the gospel's success is all about technique, but I think it does mean that God uses our individual personalities and gifts to advance the gospel. After all, this is Paul we are talking about in this episode and the book of Acts preserves enough of his sermons and gospel interactions to show us how God used his abilities to advance the Church.
Thirdly, the response was diverse. Both Jews and Gentiles came to faith. The gospel was both warmly received and later divided the city so much that the lives of the messengers were threatened (Acts 14:4-7). Both responses are indicators of an effective preaching of the gospel and should be expected even today.