Fundamental Mormon Doctrine is nearly identical to all of Christianity. However, Mormons believe in modern prophets and modern revelation. Through Joseph Smith and subsequent Mormon prophets, many truths concerning the gospel of Jesus Christ have been clarified or restored to the earth. Specific revelations or statements by Mormon leaders concerning the nature of God or life after death are rejected by most of Christianity in favor of the abstractions and unknowable doctrines of sectarian Christians. They are not the fundamental principles of the gospel necessary for salvation, but higher truths revealed for the benefit of knowledge. Anti-Mormons focus on these points of doctrine to make Mormon doctrine into something it is not and disregard the fact that Mormon scripture teaches exactly what other Christian faiths teach. These are some of the main points used in such arguments.
The Nature of God
The Mormon Church is often criticized for a belief in plural gods, but the Book of Mormon states that "there is one God and one Shepherd over all the earth" (1 Nephi 13:41). Many Mormon leaders, including Joseph Smith, have made statements about God once being a man on some other earth. The famous couplet is "As man is, God once was; as God is, man may become." When it is written that the faithful will inherit the kingdom of God, Mormons interpret this to mean that this inheritance will make one like unto God. The details and the precise meaning of this are unknown. Because of statements by Church leaders it is commonly thought that the faithful Mormon will become a god ruling their own universe. At the same time, Mormon beliefs are founded on the Bible and Book of Mormon, which clearly state that there is only one eternal God. The seeming contradiction has not gone unnoticed by critics or believers, but the possibility of multiple gods ruling over multiple universes is not a fundamental Mormon doctrine. Basic Mormon principles teach the believer to worship the one, true God.
The Mormon doctrine that God is not immaterial, but has a body, is canonized in Mormon scripture, "the Father has a body of flesh and bones as tangible as man's" (Doctrine and Covenants 130:22). This is one of the few points of doctrine that is fairly represented by Mormon Church critics because it is so plain. Mormon doctrine states that God has a glorified, immortal body, and in the resurrection all will receive a body like God's, as part of becoming like Him. Apart from this, the attributes and character of God are the same as the rest of Christianity.
The Trinity
"And now, behold, this is the doctrine of Christ, and the only and true doctrine of the Father, and of the Son, and of the Holy Ghost, which is one God, without end" (2 Nephi 31:21). This passage from the Book of Mormon is one of many in Mormon scripture that state the Father, Son, and Holy Ghost are one God. Mormon doctrine states that they are three separate beings, but they are one God. Each one has a dual nature just like the traditional view of The Trinity (The Father is God with Jesus and the Father of Jesus, Jesus is both God and the Son of God, the Holy Ghost is both God and the spirit of God), the difference is that in Mormon doctrine God is three beings, one in purpose, not in substance.
Jesus Christ
In Mormon doctrine Jesus Christ is the Son of God and also the Father of all because of His role as Savior. This dual nature is just like traditional Christianity except that Jesus is a separate being from God the Father. Jesus is both Father and Son. He is the Creator, "I am the same which spake, and the world was made, and all things came by me" (Doctrine and Covenants 38:3). This is not a 'different' Jesus that Mormons believe in. He is the only begotten Son of the Father, He sacrificed Himself for the sins of the world, He is the resurrected Savior and will judge all mankind. It is contended that the Mormon Jesus is different because Mormons believe Jesus is our brother. In all of Christianity mankind is the offspring of God, and Jesus is the Son of God, in this way He is our brother, but He is the Only Begotten and has a different relationship with the Father.
Salvation
Mormon doctrine does not claim salvation by works. The Book of Mormon states "it is by grace that we are saved, after all we can do" (2 Nephi 25:23). This doctrine differs from other Christian viewpoints because it is not a onetime, irreversible thing. Jesus Christ will have mercy on those who follow Him. In the epistle of James is written that faith is shown by works. The works do not save, but are evidence of faith and please Jesus Christ who then grants salvation through His grace. In Mormon doctrine salvation comes through the grace of Jesus Christ. And Jesus Christ will have mercy on those who follow Him.
The Bible
"And again, the elders, priests and teachers of this church shall teach the principles of my gospel, which are in the Bible and the Book of Mormon, in the which is the fulness of the gospel" (Doctrine and Covenants 42:12). This scripture shows that Mormons believe the fullness of the gospel of Jesus Christ is found in the Bible. Mormon doctrine accepts the Bible as the word of God. Some Christians cite passages from the Bible to show why Mormons are not Christian, but the Mormons believe every one of those passages. From the moment each book of the Bible was written it has been subject to interpretation. Mormons make interpretations as well, but completely accept the Bible as truth.