"The Silver Chalice" by Thomas Costain
Here's an excerpt that seems appropriate to our own day!
(Adam Ben Asher): "I am disappointed in you, Luke the Physician. I prefer you as you were before you wrapped yourself up in the toga of prophecy."
(Luke): "Must I tell you again that I am not a prophet? I am an old man who sees that things are going wrong in the world. I have always thought that the truths of Jesus could be taught best by spreading the doctrine of charity and pity. Now my heart is cold because I am beginning to see that the seed must be planted in the soil of tragedy. Only if watered by the blood of martyrdom can the tree grow to greatness."
He sighed and spread out his hands in a gesture of disillusionment.
(Luke): "The habits of men cannot be changed easily. It seems that the human mind can't be reached by kindness alone. Man understands violence better. Perhaps the Church of Jesus will gain strength from the flames of Jerusalem."