“What makes the Bible authentic?”
I don’t think you understand historical authenticity.
If an account is anonymous, historians tend not to use it. Can’t be sure who wrote it, when, or why.
If an account is not corroborated, Historians tend to hold it at arm’s length.
For example, there’s an account of Venice written about the city at the time of Michelangelo. The author boasted that most of the city was literate. On its own, can’t be sure if it was accurate or an exaggeration written by a proud Venice citizen.
On the other hand, we have the tax records of the time. Most of the business owners of that time prepared their own tax forms rather than hire a scribe. This supports the claim if a high literacy rate.
On the other hand, Moses is supposed to have written the first five books of the bible. But if he did, he wrote down a description of his funeral. Tends to make evaluators question just HOW MUCH of it’s written by Moses….
“Jesus, the historical Jesus, fulfilled the Bible and endorsed the OT.”
The bible wasn’t created until a few hundred years after Jesus’ time.
“If Jesus was God in the flesh, then if Jesus endorsed the Bible”
Which didn’t exist yet? And we’re back to Moses’ funeral….
“then God Himself tells us that the earth was created in 6 days.”
Unless Genesis is metaphor or parable….
“How much more proof do I need?”
ANY!?!?!
“Prove Jesus is real? The Holy Bible.”
You’re actually doing a hatchet job on your argument, here.