The Book of Mormon is a book of scripture comparable to the Bible.
It doesn't compete with the Bible. It's not "our version" of the Bible.
It is literally scripture just like the Bible; a collection of writings of prophets, compiled by a prophet-historian named Mormon. He is only one of many who wrote on this record.
It's a record of a people who lived in the ancient Americas, hundreds of years before and after Jesus Christ lived on earth.
They prophesied of his birth, they saw the sign of his birth, and of his death, and were visited by him days after he was crucified and resurrected. These people were the “other sheep” that were “not of this fold” that Jesus spoke of (in John ch 10).
They were mighty civilizations, filling these lands. One group came around the time God confounded languages at the tower of Babel (Genesis ch 11) and the other group were of the tribe of Judah; they came over from Jerusalem 600 years before the birth of Christ.
The book contains their teachings of God and his son Jesus Christ; their prophecies, revelations, and miracles, but also a history of their wars and conflicts. In their final battle all were destroyed except some of the nation who are among the ancestors of the American Indians.
The first book in the Book of Mormon is called Nephi; He was the son of the prophet Lehi who was guided by God to leave Jerusalem before it was destroyed by Babylon, and he also became a prophet, and was directed by God to build a ship to take his family across the sea to a land of promise.
Nephi loved the prophet Isaiah; he shares so many of his words, encourages his brothers to be strong like Moses, and remembers the struggle of the children of Israel, throughout his writings.
Isaiah prophesied that "a people like the people of Jerusalem...shall be brought low in the dust"...(and) "They shall speak out of the ground...and the book shall be delivered to someone who is learned" (Isaiah 29:1-12).
In 1828, the book was delivered by Joseph Smith to someone who is learned, to confirm the correctness of the translation. Joseph had received the record by the hand of God; an angel showing him where they had been buried, and the record was translated and published in 1829. Joseph Smith became the first prophet on the earth again after the death of Christ and his disciples.
The experiences of these people in the Book of Mormon record, their conversion stories and their faith on the Lord, are incredibly powerful, and the doctrine taught is so pure and clear to understand. So many verses of scripture in this book are so profound, and some of the most beautiful words you can read.
But maybe most importantly, it is a powerful witness that God is not silent; that He speaks to prophets in different parts of the world and commands them to keep a record, and doesn’t limit His word to what have in the Bible. Jesus talked about the need for more than one witness, of the truth of his gospel, when he told his apostles "In the mouth of two or three witnesses shall every word be established." (2 Corinthians 13:1). The Bible is one witness; the Book of Mormon is another.
With the testimony of these two witnesses, interpretation of doctrines like baptism, the spirit world, the Savior's atoning sacrifice, and so many others, are strengthened.
The Lord said that in future times (our day) there would be many people that would say "We have a Bible, and there cannot be any more Bible; we have received the word of God, and we need no more of the word of God".
He then said "Know ye not that there are more nations than one? Know ye not that I have created all men...and that I bring forth my word unto the children of men, yea, even upon all the nations of the earth? Know ye not that the testimony of two nations is a witness unto you that I am God, that I remember one nation like unto another? And when the two nations shall run together the testimony of the two nations shall run together also." This is the testimony of prophets whose words are in the Bible, and the testimony of prophets whose words are in the Book of Mormon. The Lord declared "For I command all men that they shall write the words which I speak unto them...I shall speak unto the Jews and they shall write it; and I shall speak unto the Nephites and they shall write it; and I shall also speak unto the other tribes of the house of Israel...and they shall write it." "For thus saith the Lord God: I will give unto the children of men line upon line, precept upon precept, here a little and there a little; and blessed are those who hearken unto my precepts and lend an ear unto my counsel, for they shall learn wisdom; for unto him that receiveth I will give more; and from them that shall say, We have enough, from them shall be taken away..."
I absolutely cherish and revere the Bible. Believing that God spoke to other prophets in another part of the world and that they kept records does not cause me to believe in the Bible less. It strengthens my belief. The Bible and the Book of Mormon go hand in hand.
The prophet Moroni, whose words are found near the end of the book, said "Those saints who have gone before me and who have possessed this land shall cry, even from the dust. And the Lord will bring these things forth...Out of the earth shall they come, by the hand of the Lord, and none can stay it; for it shall be brought out of darkness unto light; and it shall come in a day when it shall be said that miracles are done away...And it shall come even as if one should speak from the dead. And whoso receiveth this record and shall not condemn it...the same shall know of greater things than these."
I believe these are the words of Christ. Nephi wrote: "And if ye believe in Christ ye will believe in these words, for they are the words of Christ, and he hath given them unto me; and they teach all men that they should do good." "...it persuadeth them to do good, it maketh known unto them of their fathers, and it speaketh of Jesus, and persuadeth them to believe in him, and to endure to the end, which is life eternal. And it speaketh harshly against sin, according to the plainness of truth. ...I glory in plainness; I glory in truth; I glory in my Jesus for he hath redeemed my soul from hell." "...And if these are not the words of Christ, judge ye - for Christ will show unto you, with power and great glory, that they are his words, at the last day; and you and I shall stand face to face before his bar; and ye shall know that I have been commanded of him to write these things, notwithstanding my weakness. ...And now my beloved brethren, all those who are of the house of Israel, and all ye ends of the earth, I speak unto you as the voice of one crying from the dust."