The Greek noun akroatērion (ἀκροατήριον) refers to an audience hall or formal venue for public proceedings and judicial examinations. It appears in Acts 25 in the context of Paul's hearing before Agrippa II and Festus.
Paul's appearance before Agrippa fulfills Jesus' promise that His followers would stand before kings as witnesses (Matthew 10:18; Acts 9:15). The audience hall becomes a pulpit. Paul preaches the resurrection to the most powerful assembly he has faced. Every hall of power is an opportunity for the gospel to bear witness to the risen Christ.