Paul and Barnabas continue their missionary journey. The pattern seems to be consistent. They go to a synagogue and make many new followers of Jesus. The religious and civic leaders get either jealous or nervous and stir up the crowds against them. They escape with their lives. Sometimes they are beaten, sometimes they have stones thrown at them, and sometimes they have to run for the next town. See verse 22 "It is through may persecutions that we must enter the Kingdom of God." That is to say, it is a mistake to think that Christ followers will always enjoy the good will and wishes of the wider community. When life change through following Jesus encroaches on the vested interests of an area. . . there is trouble.
The whole episode of the Priest of Zeus wanting to sacrifice to Paul and Barnabas gives us some odd insight. Clearly Barnabas is the better looking of the two (so is called Zeus) and Paul, since he is always preaching and teaching, gets called Hermes (Mercury) the winged messenger of the gods in Greek and Roman mythology. Paul barely stops the sacrificial offering and ends up nearly getting himself killed.
Notice verse 23 "And after they had appointed elders for them in each church, . . . " There is no success without successors. Paul and Barnabas are church "planters" -- missionaries. Their job is not to lead the church community in a particular place. Their method of operation is to identify leaders, call them out, raise them up and leave them in charge. Pastors would be well served to remember this. We are not called to do all the work of ministry -- but to equip the saints for the work of ministry (Ephesians 4:11). We are not called to have to make every single decision in every single aspect of ministry. . . we are called to raise up leaders who will make those decisions and, by faith, step out in the work to which they were called.