Why is faith important?

[Question Mark]

Have you ever read Angels and Demons by Dan Brown?

no.

There's an interesting back story to a character in that book, a bloke called Max Kholer.
As a boy, he was extremely ill with a life-threatening disease, a disease that put him in extreme levels of fiery pain for days on end. Doctors begged the parents to be allowed to give him medicine that would save his life, but his parents refused, instead praying to god to save their son, and beseeching Max to pray as well.
Max did so, continually begging and praying over the course of days for god to speak to him, promising anything, &c., you get the idea I think.

After a few days, one doctor who'd stayed even after being dismissed, secretly gave him an injection that cured him over an afternoon, unbeknownst to the parents. The parents proclaimed it a miracle from god, except for one particular. The disease had ravaged Max's body quite badly before he had been cured, and left him paralyzed.
The parents were confused, sure that they had prayed enough, been contrite, and humble in their pleading for divine help, and so went to a local high ranking priest for answers.

The priest told them that god was punishing Max for not having enough faith.


Now I'm not trying to attack religion with this example, although in the story this was what Max himself was trying to do, I think. It's a fictional example after all.
My point with this story is a question I'd like to put to you:

How do you suppose that the priest came to the conclusion that Max had not been faithful enough?