What does Acts 13:51 mean?

Paul and Barnabas have explained to the synagogue in Pisidian Antioch that God's promised Savior has come. Initially, the synagogue leadership seems to be intrigued by this message. But interest turns to envy when they see how many Jews—and especially Gentiles—are hungry to learn more and follow this Jesus (Acts 13:45). The prominent Jews enlist the leading women and men in town to drive Paul and Barnabas out. In response, Paul and Barnabas follow Jesus' instruction to His disciples and shake the dust off their feet, as if to say nothing is redeemable in this town (Mark 6:11).

This isn't true, of course. They leave behind many disciples who continue teaching others about the salvation Jesus offers (Acts 13:52).

Compared to other incidents, this is a tame exit for Paul. The Jewish and Gentile leaders in Iconium will try to stone Paul and Barnabas (Acts 14:5–6). The leaders in Lystra will stone Paul (Acts 14:19). Paul and Silas will be beaten and imprisoned in Philippi (Acts 16:19–24), and their detractors in Thessalonica will follow them to Berea, eventually forcing the believers to send Paul to Athens by himself (Acts 17).

Paul outlines the persecution he endures in 2 Corinthians 11:23–28; it's interesting to see that in his long list of hardships, he includes anxiety about the churches. Paul has a tender heart. Despite the dust he leaves behind in Pisidian Antioch, he is also heartbroken when the Jewish establishment rejects their own Messiah (Romans 9:3). This describes a great tension in the lives of every mature Jesus-follower. We accept that abuse and persecution are part of spreading the gospel (John 15:20). We walk away when it's obvious our words aren't being heard (Mark 6:11). But we mourn those who refuse to hear (Luke 23:34).