True Purpose of the Holy Bible.

[Velma]

But before I go, the oldest mms fragment of the Dead Sea Scrolls is Qumran 1Q linen 390 BCE-600 CE. So when someone writes that such and such was written 4000 BCE, one must wonder how they came up with that number. Surely, there must have been writings before 390 BCE, but no one knows when the oldest part of the Bible was written and what it consisted of. Papyrus only began around the third millennium BCE and The Epic of Gilgamesh, on clay tablets somewhere between 2750 and 2500 BCE.

From what I understand, there are often clues in the language itself.  Regardless, I'm sure most of the stories in the bible were passed around orally for generations before being written down.

[Gawen]

But before I go, the oldest mms fragment of the Dead Sea Scrolls is Qumran 1Q linen 390 BCE-600 CE. So when someone writes that such and such was written 4000 BCE, one must wonder how they came up with that number. Surely, there must have been writings before 390 BCE, but no one knows when the oldest part of the Bible was written and what it consisted of. Papyrus only began around the third millennium BCE and The Epic of Gilgamesh, on clay tablets somewhere between 2750 and 2500 BCE.

From what I understand, there are often clues in the language itself.  Regardless, I'm sure most of the stories in the bible were passed around orally for generations before being written down.

Precisely. But when was Genesis (for example) first written? How much of 'Genesis' was actually written down for the first time and when? When was 'Genesis' first written in its current form? No one knows, but we hear dates bandied about all the time. Surely, the Tanahk was not originally written all at the same time and in its current form.
About all one can say for sure is that pieces of the Hebrew Bible was written before the Babylonian captivity because that's all we have to go on.

[Gawen]

Just for giggles, I did a google search on "What is the true purpose of the Bible". Here are some results:
to control mankind
The intended purpose of the Bible is to describe Yahweh and instruct in His laws and worship.
It's a learning experience for everyone, in one way or another.
To be an ingenious piece of propaganda.
God’s Word, the Bible, shows that our true purpose in living should be the doing of his divine will.
To justify otherwise immoral actions and ignorance by allowing someone to say "Well, in the Bible it says.."
to teach people to love and accept each other.
Simple: It is God's revelation to man, of who God is, who and what man is, where it all began, God's plan of salvation for humanity,
The Bible was created in the third century AD to serve as a central doctrine for the Catholic Church.
I think the bible is to help each one of us find the answers we seek.

These 10 answers were taken off just one site. Notice how they all differ. But I think the question in the OP should have been (in two parts)...What is the true purpose of the Hebrew Bible, the misnamed New Testament and why do does it include both? And, why are Bibles different?

The sad part is the answers to THAT question will be just as diverse as the answers above.