This is from Denny Burk’s blog addressing whether or not Mormonism and Christianity are compatible…. specifically whether or not Mormonism is a cult.  For the entire article CLICK HERE.  Another insightful discussion is found HERE by Dr. Al Mohler which considers voting as an evangelical for someone of another faith.

In popular usage, the word cult is associated with bizarre and sometimes threatening behavior (think David Karesh and Jim Jones). The term is seen as pejorative and an unfair attack when applied to groups who don’t live in exclusive communes and commit mass suicide. Most people would acknowledge, for instance, that the average Mormon cuts a different profile than a Branch Davidian.

The theological approach focuses the entire conversation on what is most important—the competing truth claims of the different religions. On a theological definition, cults manifest several characteristics. Typically they are founded or led by a leader who claims to have received direct revelation from God that supersedes the Bible. The theological error inherent in cults usually involves some aberration of the doctrine of the Trinity or the doctrine of Christ such that the resulting belief system is no longer Christian. In an article on “The Bible and Religious Cults,” the ESV Study Bible defines cult along these lines using the theological approach. Here is what it says:

     A “cult” is any religious movement that claims to be derived from the Bible and/or the Christian faith, and that advocates beliefs that differ so significantly with major Christian doctrines that two consequences follow: (1) The movement cannot legitimately be considered a valid “Christian” denomination because of its serious deviation from historic Christian orthodoxy. (2) Believing the doctrines of the movement is incompatible with trusting in the Jesus Christ of the Bible for the salvation that comes by God’s grace alone (Eph. 2:8-9). [p. 2631]

Under that definition, the article lists several religious groups that fit this description: Mormonism, Jehovah’s Witnesses, Christian Science, and the New Age Movement.

On a theological definition, how do Mormons measure up? Mormons deny the doctrine of the trinity and favor polytheism. They believe that the Father, Son, and Holy Spirit are three distinct gods and that there are many other potential Gods besides these. Mormons deny that Jesus Christ is the eternal Son of God. Mormons also affirm a kind of universalism (ESV Study Bible, pp. 2631-32). Focusing on what Mormonism actually teaches in contrast to orthodox Christianity, we can come to no other conclusion than that Mormonism is a cult.

Christians have an interest in defending the faith delivered once and for all to the saints (Jude 3), and we are not neutral observers when it comes to truth claims that deny the Bible. To use terms that obscure that there is a difference between Mormonism and Christianity is not helpful. Maybe cult isn’t the best communicative term since so many people only think of the sensational and sociological approaches. It’s the concept, not the term, that matters most. If someone wants to call it “organized heterodoxy” that’s fine—but I doubt the term will stick! The important thing to emphasize is that Mormonism is not Christianity.