A double minded person is one who say one thing and do another, they claim to know God and yet their actions do not live up to such claims. He thinks about two different things at the same time and can't make up his mind about anything; they are dually focused and have split opinions on the same subject. Their loyalty is divided between God and the world, and they are unstable in everything they do. James 1:8. It is God who promises to,” forgive ALL our sins and heal ALL our diseases.”(Psalm 103:3).But only if we do it God’s way and Gods standards and not in man’s way or man standards. We see many warnings in Bible being double minded. Some of them are: Elijah told Israel to stop being double-minded (1 Kings 18:21), Jesus tells us to stop being double minded (Mat 6:24), James tells us to stop being double minded ((James 4:8).
One example of being double minded is that the person may ask help from God and at the same time he may suspect Gods promises and he do not trust enough that the Lord hears and answers his prayers because he does not have true faith. One moment he trusts and believe in God, the next moment he rely on himself or any other man like doctors, experts, scientists, counselors etc instead of trusting God 100%.There are few other Christians when they get sick instead of claiming God's promise for healing they say that God can heal through their doctors. But often they forget that When Jesus was on earth and people came to Him for healing, He never once said, "Go see Luke, I heal through doctors." (Luke was a physician). Instead, Jesus healed the person directly. Our actions will reveal our beliefs. If you claim to have faith, to believe God's promises, but you don't act on them, then you really have no faith. Your faith is "dead."(James 2:26). The human wisdom tells us that in order to trust anything we should believe only when the evidence is seen. Many people including me often have said I'll believe it when I see it," but God says different he says to us "walk by faith and not by sight."(2 Corinthians 5:7).
In order to get healed by God one should have a genuine faith in God, confess and repent of his sins, follow the commandments, laws and decrees of God, Abide in Jesus Christ, humbly surrendering and submitting himself to God daily in everything ,pursuing righteousness and praying unceasingly by covering with the Blood of Jesus Christ.
We need to come to God in complete faith, without doubting and wavering .God will reject our prayers, if we are insincere, or double minded. Devil always wants us to doubt God. Jesus said, "Do not let your heart be troubled; believe in God, believe also in Me." (John 14:1).
In Psalms 32:10 reminds us that "The Lord’s unfailing love surrounds the man who trusts in him."
The Spirit of God which is our Holy Spirit creates faith in us and we should never reject what it says because God's voice is the Holy Spirit .We need to have true faith in God because he is trustworthy Hebrews 11:6 says ‘And it is impossible to please God without faith. Anyone who wants to come to him must believe that God exists and that he rewards those who sincerely seek him’.
Mark 9:23 says: Jesus said to him, if you can believe, all things are possible to him that believes.
Mark 11:24 says: Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours.
Every believer is commanded to be single minded and can claim health and healing today on the merit of the Blood of Jesus Christ making his requests known to God through prayer and supplication continuing to believe and stand for it, whether his request happens or not.