Here we will examine the life of Joseph Smith and the founding of the Mormon religion. It is not a pretty story.
Isaiah 8:19-20 says, "When they say to you, "Consult the mediums and the spiritists who whisper and mutter," should not a people consult their God? Should they consult the dead on behalf of the living? To the law and to the testimony! If they do not speak according to this word, it is because they have no dawn."
This is a fitting passage for how we should think about Joseph Smith, the founder of Mormonism. Joseph Smith talked to the dead (which are actually demons masquerading as departed "saints"), and that's where he got his revelations for the Book of Mormon.
It is too bad Mr. Smith did not pay attention to Paul's words in Galatians 1:6-8. If he had, he would have known better than to listen to an angel bringing a new gospel.
Gal. 1:6-8: "I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel; which is really not another; only there are some who are disturbing you and want to distort the gospel of Christ. But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed!"