Even though God wants you to be healed and to live in divine wellbeing, some laws govern how God's Spirit performs His duties on earth; one of such duties is to bring God's healing. The two primary ways that the Holy Spirit operates on earth are through the Word and a voice.
You get to choose whether the voice that determines what you receive from God's Spirit is your own or that of another person. The images you allow to settle in your mind have a significant impact on your prosperity and happiness.
The Bible is effective; miracles do happen. In any event, the direction of God's healing power is heavily influenced by human tendencies.