While in the initiatory waiting room, I opened up the Book of Mormon to this random scripture. It's the Lord talking about why He provided us with more scripture than just the Bible and I love what he says.
This is some very powerful scripture and it's almost as if the Lord is saying, "Come on guys - really? You think a Bible is all I gave the world? You think that I only speak to some of my children? Think about it - the planet is big and I'm God. I'm going to do what is needed to speak to ALL of my children. Here is how I have done it and it's foolish for anyone to say otherwise. Realize that all of these books of scripture testify of each other and that I am God."
2 Nephi 29:3-14
3 And because my words shall hiss forth—many of the Gentiles shall say: A Bible! A Bible! We have got a Bible, and there cannot be any more Bible.
13 And it shall come to pass that the Jews shall have the words of the Nephites, and the Nephites shall have the words of the Jews; and the Nephites and the Jews shall have the words of the lost tribes of Israel; and the lost tribes of Israel shall have the words of the Nephites and the Jews.
This is prophesy that has come to pass. The natives of the American continent have the Book of Mormon and Bible (words of Nephites and words of Jews). The Book of Mormon is also in Jerusalem. What an awesome day it will be when lost tribes return and we have their books of scripture as well. All three books will testify of the same God.
God is amazing and it only makes sense that He would give His word to His children all over the world - especially during a time when there was no internet or printing press. He gave His same word to all of His children and asked their prophets to write it down into a book.
Just think about all of His other worlds and the children living in those worlds. They also have books of scripture with the same word. It really is silly to think that the Bible is the only source of God's word amongst His vast creations. His word is not limited.