How does Mormon theology differ from biblical Christianity?

It is tempting to think of Mormonism as simply another Christian denomination with a few unusual customs, like avoiding coffee or sending young missionaries door to door. But when you compare LDS theology to historic, biblical Christianity point by point, the differences run far deeper than style or custom. They concern the very identity of God and the way a person is actually saved, the two questions every religion must answer clearly.

LDS leaders themselves have often insisted the differences are substantial rather than cosmetic, describing traditional Christian views of God as a fundamental departure requiring restoration through Joseph Smith. Taking that claim seriously means comparing the two systems honestly rather than assuming they are basically the same faith wearing different clothes.

The Bible is emphatic and repetitive that there is only one true God, who alone has always existed and always will: 'Before me no god was formed, nor shall there be any after me' (Isaiah 43:10), and 'I am the first and I am the last; besides me there is no god' (Isaiah 44:6). This is not incidental language; it is the foundation of biblical monotheism, repeated throughout the Old and New Testaments.

LDS theology instead teaches that Heavenly Father was once a mortal man who progressed to godhood, that he has a physical, glorified body, and that innumerable other gods exist across the universe, with faithful Mormons themselves able to progress to godhood. This is not a minor variation on monotheism; it is a different category of religion altogether, closer to ancient polytheism than to the God revealed in Scripture.

Biblical Christianity confesses that Jesus is the eternal, uncreated Son of God, fully God from before time began, through whom 'all things were made' (John 1:3). LDS theology instead teaches that Jesus is the spirit-child offspring of Heavenly Father and a Heavenly Mother, born in a premortal spiritual existence, and that Lucifer is his spirit brother, a claim found nowhere in Scripture and directly contradicted by texts describing the Son as eternally, uniquely divine (Colossians 1:15-17).

Scripture's picture of Christ leaves no room for a brother relationship with Satan. Jesus is worshiped by angels (Hebrews 1:6), while Satan is a created, fallen angel himself, cast down for his rebellion (Isaiah 14:12-15). Putting the eternal Son of God and a rebellious creature into the same family tree flattens a distinction the Bible treats as absolute: the difference between Creator and creature.

Biblical Christianity holds that the canon of Scripture is complete, sufficient for 'teaching, for reproof, for correction, and for training in righteousness' (2 Timothy 3:16-17), with the book of Revelation itself pronouncing a curse on anyone who adds to its words (Revelation 22:18). LDS theology instead treats the canon as open, adding the Book of Mormon, Doctrine and Covenants, and Pearl of Great Price as equally or more authoritative than the Bible, and continues to receive new revelation through its living prophet and apostles today.

Perhaps most practically important, biblical Christianity teaches that salvation is 'the gift of God, not a result of works, so that no one may boast' (Ephesians 2:8-9), secured entirely by Christ's finished work and received through faith alone. LDS theology teaches a more complex path, requiring faith, repentance, baptism, temple endowment, and ongoing faithfulness to LDS ordinances to reach the highest degree of celestial glory, effectively making final salvation dependent on a lifetime of religious performance rather than resting fully in what Christ accomplished on the cross.

None of this is reason to treat Mormon neighbors with contempt; many are kind, generous, family-oriented people worthy of genuine friendship and respect. But real love does not paper over serious theological differences. It tells the truth gently, points to the sufficiency of Christ's atonement, and trusts that the God who opened blind eyes throughout Scripture can do the same today (2 Corinthians 4:6).

The good news underneath all of this is that the true God does not require you to progress toward deity through your own effort. He has already come down to you in the person of his Son, borne your sin on the cross, and offered you full adoption as his child by faith, 'not because of works done by us in righteousness, but according to his own mercy' (Titus 3:5). That gospel is better news than any promise of becoming a god yourself, because it rests entirely on a Savior who has already finished the work.