What does Acts 17:8 mean?

Jews from the local synagogue have accused travelers—Paul, Silas, and Timothy—of promoting a king other than Caesar and have incited "wicked men of the rabble" (Acts 17:5) to start a riot (Acts 17:4–7). The people and leadership of Thessalonica are alarmed by both issues.

The Roman Empire was governed by a complicated hierarchical system. Some areas were administered by the council while others fell directly under the authority of the Emperor: the "Caesar." The position of "king" was a political appointment and not something a leader could assume. At the time of Jesus' crucifixion, the Sanhedrin convinced Pilate to crucify Jesus officially because He claimed to be king (John 19:12). For extra incentive, they obliquely threatened a riot, knowing that if Pilate lost control of Jerusalem, he would likely lose his job (Mark 15:11–15). Not long after Jesus' ascension, Caligula exiled Herod Antipas—the Herod of Jesus' adulthood—in part for treason, but in part because he assumed the title of king.

With the Roman garrison not far away in Philippi, the people of Thessalonica don't want any trouble. The charge is true that Paul is preaching that Jesus is King—it's a vital component of His identity as Messiah (Daniel 7:13–14). They don't know Jesus will not take His throne for thousands of years, long after the Roman Empire is gone. But they do know these riots will bring nothing but trouble.

It is easier to rid the city of Paul and Silas than the Jewish residents and the mob. No one can find Paul and Silas, so the authorities hold Jason, the evangelists' host, responsible and let him out on bail. If the church causes any more issues, Jason will lose a lot of money (Acts 17:9). Paul and Silas head southwest to Berea, but the church at Thessalonica is well established.