I wonder why he would be "angry" at the idea that Someone is trying to rescue him from an eternally dire predicament from which he can't save himself. If he really thought it an unlikely scenario, why would he invest so much emotion in it...I would expect he would be indifferent at best .
I suggest he is angry because he suspects it may be true.
I agree. I guess he would be really angry if I told him I am going to pray for him in the name of Jesus Christ. (which I am)