Mistake: Violating Natural Laws
Aside from a supernatural act of the Spirit (such as Jesus walking on water), gravity will make things fall toward the earth. It is a natural law. It would be pointless to try to “believe” that you would not get killed if you jumped off a tall building. (The devil tried and failed to tempt Jesus to do exactly that.)
Likewise, if you are going to keep destroying your body with nicotine, alcohol, illegal drugs or other unhealthy habits, you will have a hard time getting healed of the resulting problems. The fact that you are a Christian does not set aside natural laws concerning your treatment of your body.
You should cooperate with natural laws to promote your healing. Paul made a suggestion to Timothy along these lines in 1 Timothy 5:23. If you’re going somewhere where the water is bad, you would be wiser to avoid it if possible rather than drinking it anyway and attempting to claim Mark 16:18! If you are obese and have heart trouble, consider that you may need to lose a good deal of weight to enjoy better health. This does not negate the promises of God; it’s just common sense. (God said to renew your mind, not ignore your mind!) Yes, God is merciful and God heals, but if you live on candy bars and ice cream, you create your own trouble, and it isn’t either the devil or God causing the problems – it’s you.
You are doubleminded if you continue doing things that give you the problems of which you are attempting to be healed. Your mouth says, “I expect healing,” but your actions say, “I am making myself sick.” If you run around in the winter with no coat on (assuming that you don’t live in the tropics), you are inviting trouble, healing covenant or no healing covenant.
You can use the natural laws that relate to your body either for yourself or against yourself. Follow Paul’s advice and use them for yourself.