The grinding power of the plain words of the Gospel story is like the power of mill-stones, and those who can read them simply enough will feel as if rocks had been rolled upon them.
Humans know when it's not a good story. Unless you do this for a living, you may not know exactly why you don't like a story, but you can't fool an audience ever. They know when you have it and they know when you don't.
Curious things, habits. People themselves never knew they had them. [Witness for the Prosecution, also published in The Hound of Death and Other Stories.]
I try to turn a written thing, when I'm in trouble with it, into a spoken thing: I start imagining what I would say to someone if I were trying to tell the story or make the argument.
When you work with a good actor, there is this natural rapport and chemistry that develops over time. That chemistry helps your characters come alive and makes the story of the film that much more convincing.