The problem of the existence of a devil is important, since it relates to other beliefs which a person or his religion may uphold. The orthodox Christian concepts of the divinity of Christ, the Fall of man, the Atonement, and the inspiration of the Bible are altered when a belief in Satan is discarded.The prophets of the Church of Jesus Christ of Latter-day Saints (Mormon) take a very definite stand concerning the existence of Satan. They declare that the devil and his angels exist and that they tempt and try to deceive men. L.D.S. scriptures, given through modern revelation, not only show that Satan exists and tempts men but also confirm the authenticity of the Old and New Testaments. However, these scriptures indicate that many passages relating to Satan are missing from the Old Testament. Therefore, on the testimony of modern scripture, the Latter-day Saints maintain that the concept of Satan did not evolve into Jewish thinking and literature by natural means. Rather, the prophets of God since the days of Adam have declard that Satan exists, and some of these prophets have come fact to face with him.Through modern scripture and latter-day prophets, the Latter-day Saints believe that Satan and his angels are spirits, in the image of men, who rebelled against God and were cast down to the earth and have been here since men were upon the earth. These evil spirits have been denied the privilege of obtaining mortal bodies; therefore, they sometimes seek to possess bodies of people living upon the earth. However, they are often detected by Elders holding the Priesthood and are cast out. On occasions they have attacked mortals and in every way tried to destroy the Kingdom of God on earth.The question of Satan's existence is interrelated with many L.D.S. doctrines. The Mormon concepts concerning opposition, the Fall, the Atonement, the divinity of Jesus Christ, and the inspiration of The Book of Mormon and other modern scripture, would of necessity be changed if Satan were to be denied as real person. The Latter-day Saints state that it is through their belief in modern revelation--scripture, the prophets, and personal revelation through the power of the Holy Ghost--that they know Satan exists, that they know many things concerning his origin and career, and that they are able in many cases to expose his deceptions.