A Christian cult, or theological cult, is any religious movement that claims to belong to Christianity but distorts one or more of the essential doctrines of Christianity taught in the Bible. Since the time of Christ, heretical groups such as these have attacked various aspects of the nature of God and the soteriology of Christ.
The Bible claims to be written by God who moved men to pen His Word. We have seen that we have every reason to accept this claim. But we must eventually ask about other so-called holy books: non-biblical books that also claim to be inspired by God. In particular, what about the Quran or the book of Mormon? Are these also the Word of God?