A great deal of infrastructure was also necessary—roads, waterworks, food delivery, fortifications—were necessary to support Herod's ambitions building program.
But, how Paul told his story follows the rules of rhetoric, the means of persuasion and proof: Ethos, Logos, Pathos.
Paul was not about to launch into a defense that could release him from prison, or from his chains. He was about to launch into the story of his conversion and calling, one that would require a life-altering response from the dignitaries arrayed before him.
Festus must have felt a huge wave of relief, knowing Agrippa and Berenice could give him the full story, tightly knit as they were with Felix and Drusilla. It made all the sense in the world for him to wait just a few days for their arrival, then have them help him adjudicate what was to be done with Paul.
Philosophers have managed to prove God exists through logic – Aristotle, Plato, Descartes, Immanuel Kant, Pascal, and many others. Some of their proofs are famous. But in the case of faith, God is not an argument, or a concept. The Lord is a living being Who desires relationship with you and me. The question is, do you and I desire relationship with God?