Every human being has a spiritual nature and also a material
nature; his purpose is to subdue the material nature, which inclines him to
evil, and, with the aid of Divine Teachings, to develop his spiritual nature so
that he can manifest praiseworthy attributes. An individual who chooses to
surrender to the promptings of his material nature can sink to levels of
depravity and bestiality which are abhorrent to the discerning eye, and which
are totally unworthy of the human station. The Baha'i Teachings inform us that
there is no independent force of evil in creation, but terms such as
"devil" or Satan" are used in sacred books as symbols of the
promptings of the lower nature of man.
(From a letter dated 9 September 1992
written on behalf of the Universal House of Justice to an individual believer)