“And as he thus spake for himself, Festus said with a loud voice, Paul, thou art beside thyself; much learning doth make thee mad.”
King James Version (KJV)
26:24 Festus said, Paul, thou art beside thyself - To talk of men's rising from the dead! And of a Jew's enlightening not only his own nation, but tho polite and learned Greeks and Romans! Nay, Festus, it is thou that art beside thyself. That strikest quite wide of the mark. And no wonder: he saw that nature did not act in Paul; but the grace that acted in him he did not see. And therefore he took all this ardour which animated the apostle for a mere start of learned phrensy.
Ac 26:24 Paul, thou art beside thyself. The earnestness and fervor of Paul were so strange to Festus, his doctrine of the resurrection so novel, his manner so sincere, and his testimony so startling, that the Roman could only explain it by a mental delusion. Much learning doth make thee mad. The display of such vast knowledge of the Hebrew Scriptures to Agrippa convinced him that intense study resulted in derangement. It must not be forgotten that Festus had just come into his position, and knew little of Paul.