I'd like to answer your question with a focus on how we should be praying for healing. Those familiar with the life of C.S. Lewis might recall a healing miracle that Lewis observed around 1959. The miracle took place in the midst of prayer when Fr. Peter Bide, a former student of C. S. Lewis, laid hands on a woman that was a very close friend to Lewis. Lewis writes about the event:
I have stood by the beside of a woman whose thigh bone was eaten
through with cancer and who had thriving colonies of the disease in
many other bones as well...The doctors predicted a few months of life:
the nurses, who often know better, a few weeks. A good man laid hands
on her and prayed. A year later the patient was walking (uphill, too,
though rough woodland) and the man who took the last X-ray photos was
saying 'These bones are as solid as rock. It's miraculous...
Many believe that the woman Lewis was writing about was actually his wife Joy Davidman. If so, this could be regarded as an example of a healing that was more of a reprieve of sorts - as Joy died a few years later. In a similar manner, many modern-day Christians have observed that prayers for healing often end up being answered in a "reprieve" type manner of healing.
In a letter to a friend dated December 7th, 1950, C. S. Lewis writes about the "fides heroica" or the manifestation of the Spirit called the "effecting of miracles" mentioned in 1 Corinthians 12:10:
That this gift was promised to the Church is certain from Scripture.
Whether any instance of it is a real instance, or chance, or even (as
might happen in this wicked world) fraud, is a question only to be
decided by the evidence in that particular case. And unless one is a
doctor one is not likely to be able to judge the evidence. Very
often I expect, on is not called upon to do so. Anything like a sudden
furore about it in one district, especially if accompanied by
publicity campaign on modern commercial lines, would be to me suspect;
but even there I might be wrong. On the whole my attitude would be
that any claim may be true, and that it is not my duty to decide if it
In another undated letter, Lewis writes:
Whether any individual Christian who attempts Faith Healing is
prompted by genuine faith and charity or by spiritual pride is I take
it a question we cannot decide. That is between God and him. Whether
the cure occurs in any given case is clearly a question for the
doctors. I am speaking now of healing by some act such as anointing or
laying on of hands... As for our prayer they are united with Christ's
perpetual prayer and are part of the Church's prayer. (in praying for
people one dislikes I find it helpful to remember that one is joining
in His prayer for them.) - Letters of C. S. Lewis
That some people may more likely be used by God to pray for healing with greater temporal results can be seen in a letter where Lewis writes to Sister Penelope:
I was intensely interested in your story of the healing of the little
dog. I don't see why one shouldn't. Perhaps indeed those to whom God
allows a gift in this way should confirm their own faith in it by
practicing on beasts,... I am glad it happened...
Yet, for Lewis, the issue of bold praying (i.e. fides heroica) for miracles was rather complicated. For example, Lewis wrote on January 14th, 1953 to Fr. Don Calabria. In the letter he raises the following questions:
And now, my dearest friend hear what difficulty leaves me in the most
doubt. Two models of prayer seem to be put before us in the New
Testament which are not easy to reconcile with each other.
One is the actual prayer of the Lord in the Garden of Gethsemane ("if
it be possible...nevertheless, not as I will but as Thou wilt").
The other, though is in Mark XI v. 24. "Whatsoever you also believing
that you shall receive you shall obtain" (and observe that in the
place where the version has, in Latin, accipietis - and in the
vernacular translation, similarly, has the future tense, "shall
receive" - the Greek text has the past tense ἐλάβετε = acceptistis -
which is very difficult).
Now the question: How is it possible for a man, at once and the same
moment of time, both to believe most fully that he will receive and to
submit himself to the Will of God - Who perhaps is refusing him?
How is it possible to say, simultaneously, "I firmly believe that Thou
wilt give me this", and, "If Thou shalt deny me it, Thy will be done"?
How can one mental act both exclude possible refusal and consider it?
I find this discussed by none of the Doctors.
Please note: it creates no difficulty for me that God sometimes does
not will to do what the faithful request. This is necessary because He
is wise and we are foolish: but why in Mark XI 24, does He promise to
do everything (whatsoever) we ask in full faith? Both statements are
the Lord's; both are among what we are required to believe. What
should I do? - (Lewis, Letters: A Study in Friendship)
Lewis, in a subsequent letter, adds, "About this question which I submitted to you, I am asking all theologians: so far in vain."
In even more subsequent articles, Lewis explores this theological problem by observing that there are two basic patterns of prayer that we see in Scripture. He notes that there is a pattern “A” passive prayer and a pattern “B” prayer style – i.e. in a bold style (i.e. fides heroica). Lewis reflects on Jesus’ own prayer in the garden that the cup that he was about to drink might be spared. He raises the question: “Why was Jesus himself not sufficiently led by the Holy Spirit to pray for the right things, or to have sufficient faith that what he did ask for would be granted?" For years, Lewis struggled with these questions.
One way that Lewis attempts to resolve the paradox is by suggesting, that when a person of faith is so united with God, there is frequently something of the "divine foreknowledge" which enters his mind.
What Lewis writes about is helpful from a practical point of view. The important part of praying is to have a heart receptivity to the Holy Spirit stirring up Category B type prayers.
Still, it is important to point out that at certain times and seasons, especially in the midst of spiritual warfare, both categories of praying may not result in any tangible visible answers. God is totally sovereign. Yes, he may answer temporal prayers (both category A and/or B prayers) with temporal results. However, when this happens, these are largely sneak previews of what is to come at the end of the age.
On the other hand, God may limit his miraculous activity by only honoring these prayers in an eschatological sense. When this happens, God may be said to be preferring to hide himself rather than work signs, wonders, and miracles in response to prayer. Along this line of thought, it is helpful to consider what C.S Lewis writes in his book, The Screwtape Letters about a junior devil who mentors an apprentice and counsels him on how best to tempt a new believer away from the faith. In one of his letters to Wormwood, he writes:
He (God) wants them to learn to walk and must therefore take away His
hand; and if only the will to walk is really there He is pleased even
with their stumbles. Do not be deceived, Wormwood. Our (the Devil’s)
cause is never more in danger, than when a human, no longer desiring,
but intending, to do our Enemy’s will, looks round upon a universe
from which every trace of Him seems to have vanished, and asks why he
has been forsaken, and still obeys. How should we than pray?
In his work, Letters to Malcolm: Chiefly on Prayer, Lewis cautions: “For most of us the prayer in Gethsemane is the only model. Removing mountains can wait.”
Still, the debate goes on. There are at least two schools of thought on the issue of how often God desires us to pray boldly. One other intriguing school of thought is that the correct default position in Christianity (especially for those in missional situations) might very well reside in Category B type prayer intimations. In other words, God in small ways (e.g. in missional situations) may be frequently prompting believers to boldly pray. The divine causality of such prayer can bring about heavenly interference for positive change in our world.
In this, divine causality view of prayer, the emphasis is placed on whether we might miss out on what God is currently doing. The point is that we may often quench and abort intimations from the Holy Spirit that can release providential miracles in the world. Perhaps this is what Jesus meant when he said to his close disciples who did not experience temporal results in their prayers, "You of little faith" (Mark 8:26). Here the issue is not submission to the will of God, but the anticipation of God's response - i.e. a trust or yielding, with the pure receptivity of faith, to the Spirit's prompting for bold and persistent praying. This trust yield to the possibility of being able to even rebuke the elements of chaos in conjunction with bold prayer.
It was previously pointed out how Lewis writes: “For most of us the prayer in Gethsemane is the only model. Removing mountains can wait.”
Still, Lewis still writes in a sympathetic manner about those who hold to a high view of praying boldly:
Such a person will be tempted to reply that most of us are in fact
grievously wrong in our prayer-life: that miracles are accorded
unwavering faith: that if we dropped our disobedient lowliness and
pseudo-spiritual timidity blessings we never dreamed of would be
showered on us at every turn…This would fall in with an old opinion of
my own that we ought all of us to be ashamed of not performing
miracles and that we do not feel this shame enough…we ought perhaps to
regard the worker of miracles, however rare, as the true Christian
norm and ourselves as spiritual cripples. (Petitionary Prayer: A
Problem without an Answer)