Of all the religious traditions a Christian is likely to encounter, Mormonism is perhaps the most confusing — because it sounds so familiar.

Mormons talk about Jesus. They read the Bible. They emphasize family, community, and moral living. They use words like "salvation," "grace," and "atonement." Many Mormons are sincere, devout, and genuinely kind people who believe they are following Jesus Christ.

And yet the theological differences between Mormonism and historic Christianity are not minor. They are fundamental. Understanding them is not about being combative — it's about being honest, and about being able to have a real conversation rather than talking past each other.

The Church of Jesus Christ of Latter-day Saints was founded by Joseph Smith in 1830 in upstate New York. Smith claimed to have received a series of visions, including one in which God the Father and Jesus Christ appeared to him as two separate, physical beings — and told him that all existing churches were wrong and that he had been chosen to restore the true church.

Smith also claimed to have discovered golden plates containing a record of ancient peoples in the Americas, which he translated into the Book of Mormon. This text, along with the Doctrine and Covenants and the Pearl of Great Price, forms the additional scriptural canon of the LDS church alongside the Bible.

This is where the differences begin — and they are significant.

Historic Christianity teaches that God is eternal, uncreated, and unchanging — that he has always been God and always will be. Mormon theology teaches something very different: that God was once a man who progressed to divinity. The famous summary, attributed to Joseph Smith, is: "As man is, God once was; as God is, man may become."

This means that in Mormon theology, God has a physical body. He is an exalted, glorified man — not an infinite, uncreated spirit. The God of Mormonism and the God of historic Christianity are not the same being.

Mormonism explicitly rejects the Trinity. God the Father, Jesus Christ, and the Holy Ghost are three separate, distinct beings — not one God in three persons. This is not a subtle distinction. It is a direct rejection of one of the most foundational doctrines of historic Christianity.

The LDS church teaches that the Nicene Creed — the foundational statement of Trinitarian theology — was a corruption of the original Christian faith, introduced by Greek philosophy. The "restoration" Joseph Smith claimed to bring was, in part, a restoration of a non-Trinitarian God.

Mormons believe in Jesus — but their Jesus is not the Jesus of historic Christianity.

In LDS theology, Jesus is a separate being from God the Father. He is the firstborn spirit child of Heavenly Father and Heavenly Mother. He is the Savior, and his atonement is real and necessary — but the nature of that atonement and what it accomplishes is understood differently than in orthodox Christianity.

Mormons also believe that Jesus appeared in the Americas after his resurrection, which is recorded in the Book of Mormon.

This is perhaps the most important difference for practical conversations.

Mormonism teaches a two-tiered understanding of salvation. General salvation — resurrection — is available to virtually everyone through Christ's atonement. But exaltation — the highest degree of glory, eternal life with God, and the possibility of becoming a god — requires obedience to LDS ordinances: baptism, confirmation, temple endowment, celestial marriage, and ongoing faithfulness to LDS teaching.

In other words, grace is necessary but not sufficient. Exaltation requires works — specifically, the works prescribed by the LDS church.

This is a fundamental departure from the Protestant understanding of salvation by grace alone, through faith alone, in Christ alone.

Use precise language. When a Mormon says "Jesus," "salvation," or "grace," they may mean something quite different than you do. Ask what they mean. Define your terms. Don't assume shared vocabulary means shared theology.

Be respectful of their sincerity. Most Mormons are not trying to deceive anyone. They genuinely believe they are following Jesus. That sincerity deserves respect, even as you disagree with the theology.

Focus on the nature of God. The differences about God — his eternality, his nature, the Trinity — are foundational. If you can have an honest conversation about who God is, everything else follows from there.

Ask about grace. "Do you believe that grace alone is sufficient for salvation, or is something more required?" is a clarifying question that gets to the heart of the difference quickly.

Point to scripture. The LDS church claims to honor the Bible, though they believe it has been corrupted in places. Engaging with what the Bible actually says — about God, about Jesus, about salvation — is always appropriate.

The Christian Field Guide series covers Mormonism and other religious traditions in a format designed for everyday believers. Start with The Companion — it's free — and explore The Field Guide for a more thorough treatment.

The goal is not to win an argument. It's to love your neighbor well enough to be honest with them about what you believe — and why it matters.