I am currently editing an excellent book on the history of healing movements in the nineteenth century (James Robinson, Divine Healing). It has prompted me to think again about the issue of healing.
Being a charismatic I move in circles in which one often encounters people who sincerely believe that God promises to heal all who reach out to him in faith and do not waver.
When you challenge them as to their experience (which never matches up to their theology) the line is: "we must bring our experiences up to the word of God rather than bring the word of God down to our experience."
Now, I do think such determination to hold on to God in faith is admirable and I do think that such a belief motivates people to pray for healing and, as a result, to see more divine healing.
However, the belief seriously underestimates the theological significance of experience. Biblical writers themselves were more than happy to allow experience to shape their theology. Consider how Job's theology had to be rewriten in the light of his experience, or the impact of the exile on the theology of the inviolability of Zion, etc.
When one considers experience, the claim that "God will heal all who ask him in faith for healing" can be (a) tested, and (b) demonstrated to be false.
You see, no amount of positive testimonies of people who prayed for healing (in faith) and were healed would demonstrate the truth of the claim. Such experiences are perfectly compatible with more modest claims, such as "God will heal some of those who ask him in faith."
But it only takes one instance of a person who asked in faith for healing and was not healed to demonstrate the falsity of the claim.
And we do not have just one example—we have thousands of examples. And I mean examples of those who prayed for healing for themselves (or others) and who did not waver in their confidence that there would be (or was already) healing . . . and there was no healing.
Such experiences demonstrate conclusively the falsity of the claim that "God will heal all who ask him in faith for healing."
I do believe that God's endgame is to heal all and in the new creation all will be healed. But in the interim God allows and uses things that are less than the ideal to bring about his purposes. Healing in the present is a sign of the coming kingdom to be sought. But please let's stop promising things that are not true.