What does Acts 16:30 mean?

Paul and Silas have saved a jailer's physical life; now he asks them how he can have eternal life.

The magistrates of Philippi have illegally beaten and imprisoned Paul and Silas. In the morning, as is the custom, the officials will ban them from the city. Their mission to spread Jesus' offer of salvation and plant a church in Philippi has come to an end, for now. Instead of lamenting that their time is cut short, they sing praises to God and pray loud enough for the other prisoners to hear (Acts 16:20–25).

Apparently, their rejoicing has brought peace to their audience's hearts. When an earthquake racks the prison, opening doors and shackles, the men all stay. The jailer doesn't know this and, realizing his life will be forfeit for losing prisoners, prepares to kill himself. Paul stops him. The jailer falls at his and Silas's feet. Salvation comes to one last household before Paul and Silas must move on (Acts 16:26–29).

The jailer's words mirror those spoken by the recipients of the first gospel presentation on the first day of the church (Acts 2:37). Salvation, from a traditional Jewish view, meant following the Mosaic law. For the Romans, "salvation" could mean almost anything. Typically, people worshiped household idols for their family's well-being, city gods for their community, national gods for the Empire, and the emperor, himself. Many didn't believe in the resurrection of the dead.

Paul and Silas's message is much simpler: believe that Jesus of Nazareth died and rose again for the forgiveness of sin and accept His gift of grace (Ephesians 2:8–9). The jailer and his family do so. The jailer washes the wounds of his two prisoners; they baptize him as a sign his sins are washed away. They all finish the night rejoicing (Acts 16:31–34).