This one paragraph describes much of life back then, and Paul's personality.
Paul and Silas were beaten with rods (ouch!)! Beating Roman citizens was illegal (According to Roman law, Roman citizens were assured exclusion from all degrading forms of punishment: beating with rods, scourging or crucifixion), everyone else though, it's OK.
Paul forces the local authorities to apologize to him. Paul is a gutsy dude.
After the physical abuse Silas and Paul suffer, they stayed focussed on what their purpose is; to spread the "Good News."
When morning came, the magistrates sent the police, saying, “Let those men go.” And the jailer reported the message to Paul, saying, “The magistrates sent word to let you go; therefore come out now and go in peace.” But Paul replied, “They have beaten us in public, uncondemned, men who are Roman citizens, and have thrown us into prison; and now are they going to discharge us in secret? Certainly not! Let them come and take us out themselves.” The police reported these words to the magistrates, and they were afraid when they heard that they were Roman citizens; so they came and apologized to them. And they took them out and asked them to leave the city. After leaving the prison they went to Lydia’s home; and when they had seen and encouraged the brothers and sisters there, they departed.
Acts 16:35-40 (NRSV)
