Angel of Light

"In September, 1823, and at later times, Joseph Smith received visitations from Moroni, an angel of light, who revealed the resting place of the ancient record form which The Book of Mormon was afterwards translated." (Doctrine and Covenants - Pearl of Great Price, The Church of Jesus Christ of Latter-day Saints, 1968, Explanatory Introduction, 3rd paragraph)
According to the new testament, an angel of light is the devil. "For such are false apostles, deceitful workers transforming themselves into apostles of Christ. And no marvel; for Satan himself is transformed into an angel of light. Therefore it is no great thing if his ministers also be transformed as the ministers of righteousness, whose end shall be according to their works." (2 Corinthians 11:13-15, KJV) The Mormon church refutes the fact that the angel that came to Joseph Smith was satan. They respond by using Mormon scriptures and a couple of new testament scriptures that are taken out of context. The first scripture that is twisted to their own agenda is 1 John 4:1 which reads: "Beloved, believe not every spirit, but try the spirits whether they are of God; because many false prophets are gone out into the world." The Mormons like to use just part of this scripture to justify Moroni as an angel of God. The scripture is speaking of false prophets not angels.
Then the Mormons use 1 John 4:2-3 to give continued support for the angel Moroni. The scripture reads: "Hereby know ye the Spirit of God: Every spirit that confesseth that Jesus Christ is come in the flesh is of God. And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, where ye have heard that it should come; and even now already it it in the world." This scripture is not about angels and the validity of them. It was Johns purpose to expose false teachers and give assurance of salvation. The people of the time this letter was written were confronted with an early form of Gnostic teachings.
Joseph Smith did not have an angel of God visit him but rather the devil in angelic form.