Sorry, but you can't, and nobody can. Let me give you some examples:
- You can do real arithmetics because you stand over axioms. IIRC you have 13 axioms for real numbers.
- You can apply reason to a group of declarative sentences because you consider the status of your propositions as immutable/stationary (in terms of programming: with no side effects) and that truth matters. Then you define the concept of valid reasoning (this can be tranlated into saying that
(p1 & p2 & ... & pn) -> q is true).
- You can assert / reject a claim by the means of falsification/verification.
But each of those statements imply that you take some sort of agreement, perhaps, with an additional party while discussing.
If such party believes that the Bible is self-validating, then it is their choice to say it. Perhaps you could have a peek into Fides et Ratio, chapter 1:
By faith, men and women give their assent to this divine testimony. This means that they acknowledge fully and integrally the truth of what is revealed because it is God himself who is the guarantor of that truth.
This statement tells you the hard truth that everything is ultimately a choice: you can trust the senses (directly or indirectly via technology) or the Bible, or a strange mix.
So, no. The Bible is not self-validating. They are the ones who validate the Bible a priori. The Bible is just a bunch of pages. A book. Is as valid as LOTR saga: it depends on who wants to believe that. However, the same applies to science. Dario Sztajnszrajber (an argentinian philosophy teacher) in the debate for abortion said something similar:
la misma experiencia empírica, esto es, lo que vemos con nuestros ojos de modo inobjetable supone confiar (en la palabra “confianza” está la palabra “fe”) en la transparencia de los sentidos
Translated: the same empirical experience, that is, what we see with our eyes in an unobjectionable way implies trust (in the word "trust" is the word "faith") in the transparency of the senses.
After you reached that point, you are free. However, this is the type of free we talk about when you move out of your parent's house and say what the heck will I do now?
Now it is time to consider the choices made. Both choices involve knowledge management (you can make science out of anything, as long as you have criteria to define how to distinguish valid knowledge from invalid, and means to produce new knowledge) so the claims for science will lead you to nowhere (yes: theology is a science as well). Your discussion then quicky moves to the fields of ethics and then quickly again to a set of ad-hominem arguments.
Just remember something: religious arguments describe stuff, phenomena and entities they cannot reproduce. Just move out of the debate and challenge them to invoke their god in their aid or stop bothering you with their arbitrary claims from a book.
Then you will show them your experiments, books, and stuff and they will claim you are possessed by the Devil and you are incurring in scientism.
And remember: you can do nothing there.