Because it's the true word of God, and the undeniable proof of this is the fact that he prophecies contained therein have been coming true since the beginning of time. I'll tell you the same thing I tell everyone. All of the religions of the world (including atheism) can't be wrong, and they certainly can't all be right. By the very nature of truth there can only be one. That one truth is Jesus Christ, and the truth will set you free. If you read, and understand the Bible, you our loving God has wonderful plans for us, and satan and all the evil will be destroyed. Our God is open and up front and tells us what will happen before it does, that way we know he's telling the truth, and cause that's honesty and love, He is honesty and love in the purest form, beyond what any human other than Jesus is capable of.