I have heard some ministers talk about miraculous physical healing as something that occurs when you repeat your prayer over and over again. I once heard of a woman who prayed for herself to be healed of cancer by repeating to herself all day every day, “God is healing me.” She claimed that her cancer went into remission that way without any treatment.
Nowhere in Scripture does Jesus or anyone else tell a sick person to pray all day and every day for healing, but I do believe that this woman was telling the truth about the power of the mind to heal the body. God gave us these minds and so in a sense he is healing us through this sort of exercise. There was a famous study done where patients in hospital were told to say to themselves as much as possible, “every day, in every way, I am getting better and better.” You can look this up in any search engine for the details, but the results compared to those with negative self-talk, or no conscious self-talk were remarkable. The fact is that a positive mental attitude can have wonderful results on the body, and “praying” this affirmation is one scientific way to achieve this mental attitude.
My opinion is that this should go into the same category as medical science. It is not the same as the miraculous healing performed by Christ and his followers, but still is of God and should be considered helpful.