The Bible is full of proof that it came by the inspiration of God. The book of Mormon is completely devoid of such proof. If you accept the book of Mormon you must place your faith in one man, Joseph Smith, and accept that everything he says is the absolute and eternal truth. You must trust your eternal soul to the word of one man. If you accept the Bible as the inspired word of God you place your faith and trust in a book that was written by the Holy Spirit, without error, full of internal evidence of it's inspiration, and accepted by Jesus Christ and His Apostles. Jesus and the Apostles quoted from the Old Testament and referred to it as Scripture.
The Bible itself claims to be sufficient for eternal life:
"Beloved, while I was making every effort to write you about our common salvation, I felt the necessity to write to you appealing that you contend earnestly for the faith which was once for all handed down to the saints."
This verse teaches that "the faith" (here a reference to the Scriptures found in the New Testament) were "once for all handed down to the saints." This means that "the faith" never needs to be handed down again, or repeated. The Bible contains it all.
6 ¶ I am amazed that you are so quickly deserting Him who called you by the grace of Christ, for a different gospel;
7 which is really not another; only there are some who are disturbing you and want to distort the gospel of Christ.
8 But even if we, or an angel from heaven, should preach to you a gospel contrary to what we have preached to you, he is to be accursed!
9 As we have said before, so I say again now, if any man is preaching to you a gospel contrary to what you received, he is to be accursed!
This passage makes it clear. The Christian is never to listen to anyone who teaches anything that does not come from the gospel of Christ (as contained in the New Testament). I think it's very interesting that Paul wrote here "even if we, or an angel from heaven…." Most groups who stray from the Bible get around to claiming that an "angel" gave them a "new revelation." Paul said DON'T BELIEVE IT.
The apostle John wrote:
18 I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book; 19 and if anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life and from the holy city, which are written in this book.
This principle flows throughout the Bible. We are NEVER to add to, or take away from the Word of God. This is EXACTLY what every group does that claims independently to speak for God through "new revelations."
John writes again:
2 John 9
"Anyone who goes too far and does not abide in the teaching of Christ, does not have God; the one who abides in the teaching, he has both the Father and the Son."
Although not specifically addressing Mormonism, these verses apply to the errors of the Mormon doctrine.
The apostle Peter wrote:
2 Peter 1:3
"seeing that His divine power has granted to us everything pertaining to life and godliness, through the true knowledge of Him who called us by His own glory and excellence."
If Peter was correct (and I believe he was) then "everything pertaining to life and godliness" was available to Christians in the New Testament writings long before Joseph Smith made his claims to have a "new revelation."
The apostle Paul wrote:
2 Tim. 3:16
16 All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; 17 so that the man of God may be adequate, equipped for every good work.
The Scripture was "once for all" delivered to the saints (Jude 3) long before the book of Mormon was invented by Joseph Smith. If the “Scripture” that Paul was talking about was “adequate….for every good work” why would we need a “new revelation.”?
Other New Testament Passages to consider:
1 Tim. 4:1-2
1 ¶ But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons, 2 by means of the hypocrisy of liars seared in their own conscience as with a branding iron,
2 Tim. 4:1-4
1 ¶ I solemnly charge you in the presence of God and of Christ Jesus, who is to judge the living and the dead, and by His appearing and His kingdom: 2 preach the word; be ready in season and out of season; reprove, rebuke, exhort, with great patience and instruction. 3 For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires, 4 and will turn away their ears from the truth and will turn aside to myths.
In short, the book of Mormon is the "doctrine of demons" and the "myth" that the New Testament warns Christians to turn away from.
There is a book titled "Mormonism, Shadow or Reality" by Jerald & Sandra Tanner which exposes the many errors and false concepts taught by Mormonism. The Tanners were members of the Mormon church for many years and kept many documents with them when they left the church which prove the errors and deceptive practices of the Mormons. The Tanners have a book store at 1350 South West Temple, Salt Lake City. I believe you can still order the book from the "Modern Microfilm company" box 1884, Salt Lake City, Utah 84110.