In the New Testament of the Bible, Jesus made multiple comments that because the person believed and had faith, that they were healed. The lame who couldn’t walk, the blind who couldn’t see, and the person with leprosy whose skin was contagious as examples.
There was another time when the disciples were healing and casting out demons but they could not help this one case. Jesus stated that this demon was special and that it could not be cast out like the other ones. And that the disciples were to required pray and fast to cast out that kind of demon.
“And Jesus rebuked the demon, and it came out of him, and the boy was cured instantly. Then the disciples came to Jesus and asked privately, Why could we not drive it out? He said to them, Because of the littleness of your faith [that is, your lack of firmly relying trust]. For truly I say to you, if you have faith [that is living] like a grain of mustard seed, you can say to this mountain, Move from here to yonder place, and it will move; and nothing will be impossible to you. But this kind does not go out except by prayer and fasting.”
Matthew 17:18-21 AMPC
Now, there is truth that belief and faith are paths to healing. In fact, research shows that it in physical therapy cases of low back pain, if a person doesn’t believe that one will get better, that their prognosis is poor.
When I first meet a patient and I’m not sure about their prognosis–in the spirit of Evidence Informed Practice (EIP)–I will sometimes explicitly ask, “Do you think that you’re going to get better?” If they say, “Yes,” then I know that they’re going to get better. If they say, “No,” then the same research recommends giving the patient other options so that they can try other means to reach their goal.
Now, for the ones who could not be helped at all, I first get to have to courage to ask the “why” question, then my teachers and mentors can show and tell me “why,” and then I then I get to take time away from work to gain more knowledge, skill, and wisdom to be able to help this person from their ailment.