Acts 26:24 in the King James Version
And as he thus spake for himself, Festus said with a loud voice, Paul, thou art beside thyself; much learning doth make thee mad.
Context
23 how the Christ must suffer, and how, by the resurrection of the dead, he would be first to proclaim light both to these people and to the Gentiles.”
24 As he thus made his defense, Festus said with a loud voice, “Paul, you are crazy! Your great learning is driving you insane!”
25 But he said, “I am not crazy, most excellent Festus, but boldly declare words of truth and reasonableness.