If you are looking to prove the validity and authority of the Bible based on extra-biblical evidence, consider this:
For those who make their doctrine of Scripture dependent on historical research into its origination and structure have already begun to reject Scripture’s self-testimony and therefore no longer believe that Scripture. They think it is better to build up the doctrine of Scripture on the foundation of their own research than by believingly deriving it from Scripture itself. In this way, they substitute their own thoughts for, or elevate them above, those of Scripture (Reformed Dogmatics: Prolegomena, vol. 1 [Grand Rapids: Baker Academic, 2003], 424).
Spirit of Christ, let those who seek the Truth, do so “believingly.” Open eyes to see the wonders of your law (Ps 119:18).
Soli Deo Gloria, dss