And the angel spake unto me, saying: These last records, which thou hast seen among the Gentiles, shall establish the truth of the first, which are of the twelve apostles of the Lamb, and shall make known the plain and precious things which have been taken away from them; and shall make known to all kindreds, tongues, and people, that the Lamb of God is the Son of the Eternal Father, and the Savior of the world; and that all men must come unto him, or they cannot be saved.
And they must come according to the words which shall be established by the mouth of the Lamb; and the words of the Lamb shall be made known in the records of thy seed, as well as in the records of the twelve apostles of the Lamb; wherefore they both shall be established in one; for there is one God and one Shepherd over all the earth. 1 Nephi 13:40-41

Sometimes the Book of Mormon says things that contradict other things it preaches.  In this passage, it states:

1. The testimony of the 12 apostles is true (the Bible is true)
2. The Lamb of God is the Son of the Eternal Father (Jesus Christ is the Son of God)
3. If Jesus is the Son of the Eternal Father, He is God.
4. Jesus alone is the savior of the world.
5. Everyone must come to Him or they cannot be saved.
6. They must obey His commands.
7. There is only ONE God and ONE Shepherd over all the earth.

This means the BIBLE is true.  Jesus is God.  Only Jesus can save people, not works, not the church, not Joseph Smith.  There is only ONE God, not many gods throughout time.