While Reiki is spiritual in nature, it is not a religion. It has no dogma, and there is nothing you must believe in order to learn and use Reiki. In fact, Reiki is not dependent on belief at all and will work whether you believe in it or not. Because Reiki comes from God, many people find that using Reiki puts them more in touch with the experience of their religion rather than having only an intellectual concept of it.
While Reiki is not a religion, it is still important to live and act in a way that promotes harmony with others. Mikao Usui, the founder of the Reiki system of natural healing, recommended that one practice certain simple ethical ideals to promote peace and harmony, which are nearly universal across all cultures.

During a meditation several years after developing Reiki, Mikao Usui decided to add the Reiki Ideals to the practice of Reiki. The Ideals came in part from the five prinicples of the Meiji emperor of Japan whom Mikao Usui admired. The Ideals were developed to add spiritual balance to Usui Reiki. Their purpose is to help people realize that healing the spirit by consciously deciding to improve oneself is a necessary part of the Reiki healing experience. In order for the Reiki healing energies to have lasting results, the client must accept responsibility for her or his healing and take an active part in it. Therefore, the Usui system of Reiki is more than the use of the Reiki energy. It must also include an active commitment to improve oneself in order for it to be a complete system. The ideals are both guidelines for living a gracious life and virtues worthy of practice for their inherent value.