Arguing with a belief.

beliefnet :

"To argue with a belief is to tilt at a windmill. The sails keep going round and round, with any damage to the sails ignored rather than repaired. One gets the impression that if the sails are shredded completely, the believer will turn the crank hermself to keep the sails moving."

One gets to the point that there is nothing left to tilt at. The sails are completely gone. At that point one can only say, as belief is usually God related, "God Bless You, it is all you have left."