The doctrine explained on this page is generally considered heretical by Christians. Its inclusion as a doctrine is not an endorsement of its truthfulness. There are many false doctrines. 2 Peter 2:1–3
This page not only explains the doctrine, but hopefully why it is widely known to be false. It is good to be aware and ready to give an answer to false doctrines. 2 Timothy 4:2–5
Unlike Christianity and Judaism before it, the Church of Jesus Christ of Latter-Day Saints, more commonly and helpfully known as Mormonism, denies that there is one eternal, unchanging, sinless, omnipotent God. Instead, it teaches—though rarely openly—the blasphemy that God was once a sinful human Himself who became a god through Mormonism, that God has multiple divine wives, that Jesus is a separate, lesser god, and that all humans can become gods if they tithe, get married, and follow the Mormons' rules well enough. This belief is simply enunciated in the doctrinal couplet:
As man now is, God once was:
As God now is, man may be.
This accepted belief is in opposition to Christianity and the Bible for numerous reasons.
Most obviously, this denies the eternality of God. The Mormon god is not the same today as he was in the past. The God of the Bible created the very concept of time itself, never has changed and never can change at all.
Hebrews 13:8 Jesus Christ the same yesterday, and to day, and for ever.
Malachi 3:6 For I am the Lord, I change not; therefore ye sons of Jacob are not consumed.
James 1:17 Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning.
This change in doctrine has huge practical implications. If someone changed before, he can change again. A Mormon has no reason to trust that his gods will remain the same and be good, loving, or powerful in the future.
Similarly, a being with a beginning cannot be omnipotent for it cannot control before it was, and it is as limited by the march of time as anyone else. It's hard to logically understand how a being bound by time could even know the future at all.
The existence of an innumerable quantity of other gods limits them even more. For each god's power cannot exceed all of the others. At best, the god you worship has power over its little kingdom, but such power is inconsequential compared to the God of the Bible who made the entire universe, spoke the stars into being, and is Lord of lords, without limit. A Christian need never worry if something is too big for God.
It might be too obvious to be worth mentioning, but this is in direct contradiction with the core Judeo-Christian doctrine of Monotheism:
Monotheism is the belief that there is only one God. Monotheism is a core doctrine of Christianity, which believes in one triune God, Yahweh.
Throughout the Bible, God makes it clear that He is the only God there is. Mormons believe that “God” in the Old Testament was a premortal Jesus who only revealed the existence of his father after he was born, and that humans can become gods too if they follow Mormon teaching. Yet the God of the Bible explicitly says there was no god before Him nor can anyone ever become a god in future:
Isaiah 43:10–11 Ye are my witnesses, saith the Lord, and my servant whom I have chosen: that ye may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me. I, even I, am the Lord; and beside me there is no savior.
Our triune God is one God, and it is the oldest lie in the book to teach otherwise. Literally, this was the lie Satan used to coax Eve into committing humanity's first sin:
Genesis 3:5 For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil.
The Church of Jesus Christ of Latter-Day Saints continues to repeat Satan's lies for him now thousands of years later.
Even on the smaller scale, the belief that God the Father and God the Son are separate gods, beyond being polytheistic, also contradicts the Bible's teaching of the Trinity and Christ's oneness with God.
John 10:30 I and my Father are one.
John 14:9 Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father?
The Bible is clear that Jesus was not created by God, but is Himself the eternal God:
John 1:1–3 In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made.
Mormons say they believe Jesus is equal with God, yet in Mormon thought the divinity of Jesus is different and often subtly consider lesser than that of the Father. Jesus is seen as a oldest child of God, sibling to all other humans, who is merely the most obedient and intelligent of men. He is said to have progressed the furthest of all humans towards being like God, but he is still seen as behind the Father.
None of this is in the Bible, which instead states simply and clearly that not only is Jesus one being with the Father, but that He is an equal person of the Trinity:
Philippians 2:5–6 Let this mind be in you, which was also in Christ Jesus: who, being in the form of God, thought it not robbery to be equal with God:
As Mormons believe that God was once as we are and since we are sinners, logically the Mormons believe God was, at least earlier in his life, a sinner. This is perhaps the most blasphemous of all Mormon beliefs. If God is a sinner, then he is no better than we are. The LDS god is indeed a great hypocrite to judge any humans when he himself committed those sins. Furthermore, there would be no hope in Christ's sacrifice if God Himself was not perfect. If God was a sinner, then He could not have paid for our sins.
Even disregarding the past, the LDS belief in Jesus being a separate god who was physically conceived with Mary. Some Mormon founders stated this means their god physically raped the teenage Mary to impregnate her. Official doctrine does not have a position on how his conception was achieved beyond stating somehow their god's sperm got into her. This is after the fact that the Mormon god already had a polygamist harem of god-wives himself. Obviously, Christianity and even a non-believing person's natural conscience will state that these would be incredibly wicked actions for anyone to commit and completely at odds with any claim of perfection or even goodness, yet such statements were the natural beliefs of the founders of the Church of Christ of Latter-Day Saints, who themselves had up to the 50s of wives, many being teenagers likewise, which doctrine taught was so holy so as to almost ensure they would join the Mormon pantheon.
The Christian God however is not like the Mormon god. God is perfect and always has been. Even the sinless angels cannot look at God without crying out “Holy, holy, holy”. God is so holy that He cannot even look upon sin. Habakkuk 1:13 Unlike worshipping one changing, sinful, polygamist god out of many, Christians can trust in the unchanging, perfect, holy God of the Bible.