Sometimes people fail because they have not confidence in the Physician. The very first requirement of this Doctor is, that you trust Him, and trust Him implicitly, so implicitly that you go forward on His bare word, and act as if you had received His healing the moment you claimed His promise. But no one would expect to be healed by an earthly doctor as soon as they obeyed his directions.
You must do what the Great Physician tells you, if you expect Him to make you whole.
You cannot expect to be healed if you are living in sin, any more than you could expect the best physician to cure you while you lived in a malarial climate and inhaled poison with every breath. So you must get up into the pure air of trust and obedience before Christ can make you whole. And then, if you will trust Him, and attend to His directions, you will find that there is balm in Gilead, and that there is a Great Physician there.