Why the Bible?

Simple Answer : Because Jesus said so.

Why Jesus? : Because no other "god" sacrificed Himself for our sins, and rose again.

Was Jesus God? Yes, but not in ALL his glory, if He was in ALL His glory then ALL evil would have been consumed immediately.

Heb 12:29
29 For our God is a consuming fire.

That is why he was called the "Son" of God, or you could say "part" of God came to earth, humbly and in low estate.

In no other religion has a "god" lowered himself to human form to sacrifice himself and powerfully resurrect.

At first these verses seem contradictory, but if you understand that His being in the flesh, makes Him lower than the angels who are in a higher dimension, but not lower in RANK as Heb. 1:4 clarifies

Heb 2:9
9 But we see Jesus, who was made a little lower than the angels for the suffering of death, crowned with glory and honour; that he by the grace of God should taste death for every man.

Heb 1:4-5
4 Being made so much better than the angels, as he hath by inheritance obtained a more excellent name than they.
5 For unto which of the angels said He at any time, Thou art my Son, this day have I begotten thee? And again, I will be to him a Father, and he shall be to me a Son?

If you continue reading you will see Jesus is to be worshipped (not angels, or humans):

In other "religions" angels, humans, or ancestors are worshipped, when none of these have ever died for their followers!

Heb 1:6-9
6 And again, when He bringeth in the firstbegotten into the world, He saith, And let all the angels of God worship him.
7 And of the angels He saith, Who maketh his angels spirits, and His ministers a flame of fire.

Here the Son of God is called God (because Jesus is God)
8 But unto the Son He saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom.
9 Thou hast loved righteousness, and hated iniquity; therefore God, even thy God, hath anointed thee with the oil of gladness above thy fellows.

Simply put ONE God - three offices

So WHY the Bible?  A Sinless Man, named Jesus, who is to be worshipped as God quoted only the Bible!  He didn't quote other historical books known at the time, but only the Bible (the prophets from Moses to Daniel).

So, we have no other Saviour, and we have no other book by which to follow, but the Bible and Jesus Christ.

We musn't miss the point that God Himself payed us a visit in our "lower" form.  Has any other "god" cared that much, or even claimed to care that much? 
Unequivocally, the answer is absolutely NOT.

Being the Creator, our God sent us Word to teach humans about Himself, but not only the WORD, the Creation itself testifies of Him.  "The Heavens declare the Glory of God", as the homepage gives a little sample of the testifying of Him who created it all.

Once you realize, that the Bible is Word directly from God, then at once you desire to know Him, the more you read and learn, the more your love for Him grows.