“For it seems to me unreasonable, in sending a prisoner, not withal to signify the charges against him.”
Indeed Festus' previous training had actually demonstrated to him that to send a prisoner to be judged against whom no charges have been made seemed a little unreasonable! (It is possible to think of another word for it).
We must not, however, criticise Festus too much. He had been sent as procurator to a country which was a hotbed of trouble, whose leaders were notorious for complaining to Caesar, whose complaints had contributed to the downfall of the previous procurator, and who were vociferously claiming that Paul was an evil troublemaker. And he was new to the job, and wanted to succeed and keep this hotbed under control. In the light of that we must recognise that he had shown the restraint of an honest, if somewhat wary, man, who found himself in an impasse. What he was looking for was backing and support so that he would be able later to excuse himself if necessary, and a reasonable charge to lay against Paul in sending him to Caesar. Feelings in Judaea were just too high for him to dare to release him.