Mikao Usui, the founder of Reiki, brought to us the Reiki Precepts and described Reiki as a mental and spiritual improving aid. Using these precepts as a 'how to live' will help us understand; Healing your own spirit is paramount. It is true to say that to heal the physical you must first heal the mental/emotional cause. A copy of the original Japanese Kanji and the literal translation are available at the link above.
The Reiki precepts teaches us: