Acts 25:10

But Paul said, I am standing before Caesar's judgment-seat, where I ought to be judged: to the Jews I have done no wrong, as thou also very well knowest. If then I am a wrong-doer, and have committed anything worthy of death, I refuse not to die; but if none of those things is true whereof they accuse me, no man can give me up unto them. I appeal unto Caesar.

This was absolutely the only avenue left open to Paul. The namby-pamby Festus knew he was innocent, but insisted on taking him to Jerusalem, where Paul would certainly have been murdered. "Woe unto thee, O land, when thy king is a child" (Ecclesiastes 10:16). Festus was a "child" in understanding. Paul's rebuke of this governor, in such an appeal, was fully deserved; but his abrupt appeal to Caesar must have come as a shocking surprise to Festus. Having his very first case appealed to Caesar was not exactly the way he had hoped to begin his term as governor. Still, it did get him "off the hook" with regard to those whom he sought to please in Jerusalem; and he was probably glad that Paul had appealed.

I am standing ... has the meaning of "I have been standing a long time" at Caesar's judgment-seat, Festus' tribunal; and "I ought to be judged" here, rather than before some court in Jerusalem.

I refuse not to die ... Paul meant by this that he was not appealing for the sake of avoiding punishment for a crime, but in order to prevent his being murdered. "By this appeal, he delivered himself from the injustice of a weak and temporizing judge."[7]

Every Roman citizen had a right of appeal from lower tribunals in the empire to the final court of the emperor in Rome; and once an appeal was registered, it had the effect of stopping all further litigation and transferring the case to Rome. Thus, it was his Roman citizenship which saved Paul's life here.