“While the Church of Jesus Christ of Latter-day Saints is established for the instruction of men; and it is one of God’s instrumentalities for making known the truth yet he is not limited to that institution for such purposes, neither in time nor place. God raises up wise men and prophets here and there among all the children of men, of their own tongue and nationality, speaking to them through means that they can comprehend. … All the great teachers are servants of God; among all nations and in all ages. They are inspired men, appointed to instruct God’s children according to the conditions in the midst of which he finds them.”

B.H. Roberts

http://www.lds.org/ensign/2000/08/a-latter-day-saint-perspective-on-muhammad?lang=eng