Paul is stating a hypothetical situation. If he were guilty, he would accept the punishment, but he knows that he is not guilty. (See: [[rc://en/ta/man/translate/figs-hypo]])
Possible meanings are 1) Festus does not have the legal authority to hand Paul over to these false accusers or 2) Paul was saying that if he has done nothing wrong, the governor should not give into the request of the Jews.