God said, “If you listen, listen obediently to how God tells you to live in his presence, obeying his commandments and keeping all his laws, then I won’t strike you with all the diseases that I inflicted on the Egyptians; I am God your healer.” ~ Exodus 15:26, The Message

God showed Moses a tree that made the bitter water sweet. This was foreshadowing the Cross. Even under the Old Covenant, God provided a cure for physical diseases – not only to restore you to health but maintain you in health.