Some Jews in the church begin to insist that the Gentiles keep Torah, especially in being circumcised, to be considered true Christians. Paul and Barnabas resist this. They take the disagreement to Jerusalem, the supreme court of appeal of apostles and elders. Peter and James side with Paul, and send some delegates back to Antioch with a letter essentially binding them to the covenant with Noah, not that with Moses.
Paul wants to go back to visit the churches again, but not with John Mark, who left them before. Barnabas insists he come, so Barnabas and John Mark go, and Paul takes Silas with him, separately.
Paul discovers Timothy in Lystra, and has him get circumcised so as not to stumble the Jews there. Interesting, after chapter 15!
Seeking to go north to Asia, Paul and Silas and Timothy are hindered. The Spirit directs them west to Macedonia instead. Lydia is converted in Philippi. The Gospel is dismissed until it starts having an impact. When a cash cow psychic is exorcised and thus ruined, they throw Paul in jail. This just furthers the Gospel, converting the jailer and his household. Then Paul insists the magistrates admit their fault in jailing them. Doesn't seem very humble, according to the pietist, perhaps, but it was important to set the public record straight that the enemies of Christ sought the injustice, not His followers.