I believe many who claim to believe in the ability of God to heal and those who claim to believe it is generally His will to heal are really unsure of His will.
It is almost like the calvinist’s believing God has some mysterious secret will that is contrary to what He wrote in His Word. As if His secret sovereign will overrides and contradicts what He revealed in His Word and what He promised.
Even though many are not healed you cannot argue from the Bible that it is because it was the will of God.
For faith to truly be exercised and to truly pray the prayer of faith there must be no doubt about what the will of God is in a matter.
James 1:6-8- But let him ASK IN FAITH NOTHING WAVERING. For he that wavereth is like a wave of the sea driven with the wind and tossed.
For LET NOT THAT MAN THINK THAT HE SHALL RECEIVE ANYTHING OF THE LORD.
A double minded man is unstable in all his ways.
To truly ask in faith and pray the prayer of faith there must be no wavering and no doubt as to what the will of God is in the matter.
Any underlying doubt or wavering will totally undermine the prayer of faith.
The same author in the same book records a few chapters later:
James 5:14-15- IS ANY SICK AMONG YOU? Let him call for the elders of the church; and let them pray over him, anointing him with oil in the name of the Lord:
AND THE PRAYER OF FAITH SHALL SAVE THE SICK, AND THE LORD SHALL RAISE HIM UP
For the elders as well as the one being prayed for to pray and believe in faith there must be no wavering or doubting as to what the will of God is.
1 John 5:14-15- And this is the confidence that we have in Him, that, if we ask anything according to His will, He heareth us:
And if we know that He hear us, whatsoever we ask, we know that we have the petitions that we desired of Him.
We can have no confidence that God will hear and give us the answer to our prayers if we are not sure about what the will of God is.
As long as there is underlying doubt or wavering as to what the will of God is then it cannot be the prayer of faith and confidence in God hearing and answering our prayer and petition to heal the sick.
We must also have confidence that we are in a right heart condition before God for our prayers to be heard and answered:
1 John 3:20-22- For if our heart condemn us, God is greater than our heart, and knoweth all things.
Beloved, if our heart condemn us not, then have we confidence toward God.
And WHATSOEVER WE ASK WE RECEIVE OF HIM BECAUSE WE KEEP HIS COMMANDMENTS AND DO THOSE THINGS THAT ARE PLEASING IN HIS SIGHT.
When these conditions are met of knowing our heart is right with God and knowing what the will of God is we can boldly ask, seek, knock until we obtain the answer. Luke 18:1-8, Mark 9:23-29, Matthew 17:19-21