Luke doesn’t come right out and say so, but Festus seems to be two different people in this narrative. The first Festus seems to have been aware of the previous plot of the Jewish authorities to have Paul killed (Acts 25:2-3; cp. Acts 23:12-15, 20-21, 28-30) and resists the repeated supplications of the Jewish authorities to have Paul brought to Jerusalem for trial. However, the second Festus seems very willing to use Paul as a political pawn to secure for himself a stable alliance between Rome and the local Jewish ruling class. What are we to make of this?
It seems evident to me that Festus knew of Paul’s predicament, including his trial before Felix and the events that transpired up to that point. There also seems to be an interim of several months between Felix’s removal as governor of Judea and Festus taking up that office. If we place Felix’s removal in the late summer or early fall of 58 CE, Festus would not have arrived in Judea until after winter in 59 CE, probably in late spring or early summer. Festus could have become familiar with Paul’s case as a matter unresolved by Felix while in Rome, awaiting a safe departure to the east, or he could have become familiar with Paul during his (Festus’) three days spent at Caesarea before going up to Jerusalem. Certainly, if Paul was under ‘house arrest’ in Herod’s palace his case would have been a curiosity at the very least. Paul’s own mention that Festus knew very well that he (Paul) was innocent (Acts 25:10) might very well indicate a prior, private consultation with the governor, before he went up to Jerusalem. If this is so, then Paul’s appeal to Caesar (Acts 25:11) would not only have indicated a distrust of Festus’ intentions, but a betrayal by Festus to possible confidential assurances he made to Paul during those first three days.
What happened that changed Festus from one apparent persona to another totally opposite in Luke’s narrative? I believe something occurred during the governor’s ten days he spent at Jerusalem or during his two day trip from Jerusalem to Caesarea in company with the Jewish elite. The governor’s statement: “let the influential men among you go there with me…” (Acts 25:5 – NASB) may point to a concession Festus made to their repeated requests, and not reflected in his initial response. Festus may have intended to convene his court and officially release Paul on the findings of Felix’s court, but at Jerusalem he seems willing (after repeated requests of the Jewish authorities) to permit them to come to Caesarea to submit any (new) charges against the man, and he would consider their merit before he rendered his decision.
The fact that the Jewish leaders desired to have Paul ambushed (Acts 25:3), indicates that they didn’t perceive they had a very strong case that would stand up in a Roman court. Their urgency to have Festus resolve the problem of Paul in their favor expresses the zeal and stubbornness of religious desire. Political progress is achieved through discussion and compromise, but religious zeal never compromises its intentions. This can be seen in the first century Jewish authorities and Rome, and in our own day in American politics and the religious right (which provokes an equally obstinate secular left). This is dangerous stuff where justice is often compromised as a sacrificial pawn to achieve immediate results.
 Acts 25:2 the Greek word (G3870) translated besought (KJV) or urged (NASB) is in the imperfect tense meaning “they kept on begging him”. See Ben Witherington: The Acts of the Apostles, page 720 including footnote #351.
 There was a change in the coinage of Judea in the 5th year of Nero’s reign (58-59 CE). It is unlikely that this would be the work of an outgoing procurator; see Witherington, The Acts of the Apostles, page 716. Moreover, Eusebius claims Festus began his reign in Judea in the 10th year of Abrippa II, and Josephus puts the beginning of Agrippa’s reign in 50 CE. Therefore Agrippa’s 10th year would have been 59-60; see Witherington, The Acts of the Apostles, page 718.