Firstly, the prison episode: the jailer would have been one of the sturdy middle class Romans, possibly an ex-soldier. His work was not pretty, but generally not taxing, until this episode with Paul and Silas! The jailer knew the way that it would be if prisoners had escaped so set out to kill himself before the authorities had their way, as we have read previously. Paul and Silas were singing hymns at midnight: you can take away someone's freedom, but you cannot take away the presence of Jesus! The jailer had locked the door and put him in stocks, but Paul didn't begrudge him the opportunity to be saved. However, after this incident-after the beating, the imprisonment, the stocks- Paul claims his Roman citizenship and by rights anyone who physically punished a Roman citizen was liable to death. Paul did this so that the believers left in Philippi would have his protection even in his absence. The Jailer proved his change of heart by what he did: binding the wounds of Paul and Silas and giving them food. Our declared change of heart must be matched by our change of deeds.
The coming of Christianity to Thessalonica was an event of prime importance. The main street in the city was part of the great Roman road which went from the Adriatic sea to the Middle East. If Christianity could be firmly founded in Thessalonica it could spread both east and west easily along that highway. The journey from Philippi to Thessalonica was one hundred miles, so this took time! Paul headed straight for the synagogue and this raised the ire of the Jews as Paul's great success was in bringing the Greeks who attended the synagogues to Christ: the Jews were going to lose their Greek adherents! So, they stirred up the rabble, dragged them before the magistrates and charged them with preaching political rebellion. We can note here that the Jews in this city knew how effective Christianity was and took underhand methods to quash it at an early stage. We know from Paul's two letters to the Thessalonians that they didn't succeed!