Taken by themselves these words seem to be talking about curing physical disease, but the words that follow, "and if he be in sins, they shall be forgiven him",

Taken by themselves these words seem to be talking about curing physical disease, but the words that follow, "and if he be in sins, they shall be forgiven him", speak expressly of a spiritual effect on the receiver. Also relevant is that most of the New Testament epistles are about the condition of the soul (as believed), and not a workout and health guide for the condition of the body.