As soon as Paul arrives in Caesarea, prominent Jews from Jerusalem approach Festus for a “favor,” to release Paul to their custody. What we know about Festus is generally good, especially when compared to Felix. He dealt quickly with two separate messianic movements (Antiq. 20.8.10). Unfortunately, Festus died after less than two years in office (A. D. 61-62) and his replacement Albinius was not an able administrator at all.
The language of their request points to a formal alliance. If Festus expects to have the support of the local elite, then he needs to hand Paul over to them for justice rather than release him. It is quite remarkable that there is still a plot afoot to assassinate Paul (25:3). It has been two years since Paul’s alleged offense yet there is still a faction which considers him guilty of desecrating the Temple. While this seems extreme, remember that bringing a Gentile into the court of the (Jewish) men was nearly as bad as the blasphemy committed by Antiochus IV Epiphanes. That act of desecration was a major factor in the Maccabean revolt. These enemies of Paul are burning with the same Zeal for the Law Paul had in Acts 9 when he traveled to Damascus to arrest followers of the Way.
Festus sees that there is nothing about Paul that requires punishment. In fact, these are not even real accusations being made against Paul! Paul’s accusers are not present, therefore the very basis of a case against him in Roman law is missing. This was Paul’s point in his defense before Felix (his accusers are the Asian Jews, who disappear when the action moves to Caesarea).
Luke only briefly comments on Paul’s defense before Festus, although he adds the claim that Paul has neither offended the Temple or Caesar. This is the first time that Paul has emphasized that he is not guilty of anything under Roman law. Paul clearly realizes that his only chance at justice is to rely upon his citizenship.