Nice play on a phrase Tony.
But it does not actually prove anything one way or the other to say that God is self validating.
The question is not whether God is self validating or not. The question is whether various religions are...only...self validating. And cannot be proven up by 3rd party means.

From the Book of Marty...
I firmly believe that God is or is-not whatever God is or is-not.
What I may want God to be or believe God to be or whatever any earthbound mortal may profess God to be, is an aside. The fact remains that God is or is not whatever God is or is-not. That fact does not need validation. It is unequivocally true...unless someone can imagine a form to God and that imagined form will some how become God.

Here is the tough part for many people...
I accept that I may never actually find out what God is or is-not. That "closure" may simply not be available to humans. Hopefully it is.
Nothwithstanding that, I am two months from 70 and if this life is all I get, I am extremely grateful for the opportunity to have lived it.

Book of Marty
Page one, Verse one, paragraph one.