I still wonder how KJVO, a strictly MAN-MADE doctrine, ever wormed its way into any IBF body of doctrines, as all their other docs have at least SOME Scriptural support. I think this was concurrent with the rise of KJVO in some other churches' SOFs.
I hope answering your question is on topic. Those churches that support the KJB only position in their statements of faith believe there is much scriptural support for their position.
Is there a verse in the scriptures that says God will preserve his Word in an English version called the King James Bible? No. And if it did say that, you can bet your last dollar that the ol' devil would publish 100 different bibles that were very different and call them all the King James just to confuse folks.
What the scriptures do say is that God will preserve his scriptures even after heaven and earth pass away. So, the true and pure Word of God is out there, it is just up to us to identify it.
How do we identify it? Most of this evidence is historical. We have the Received Text and we have early writings of church fathers and scriptures written in other languages that support it. That is historical and scholarly evidence.
We also have a historical evidence of history itself. We have the obviously corrupt RCC church with it's scriptures based generally on the Alexandrian texts. We also have a history of churches that many consider more pure and faithful to Christianity that followed the RT. We see the men who gave their lives to publish scriptures based on the RT. We see the church coming out of darkness and the scriptures made available to the common man. We see a period of great evangelism where the gospel was taken to nations all over the world.
So, this historical evidence is considered as pointing to that true text God said he would preserve. We also see evidence of the other line of scripture that points to a very corrupt church that literally killed millions of people over the centuries, very un-Christlike behaviour.
And so churches believe they have the many scriptures that say God will preserve his word forever. One of the SoF I showed showed the many scriptures they based their belief upon. But we also have historical evidence that points to these scriptures being fulfilled, even if a particular line of text is not specifically named.
Matt 7:20 Wherefore by their fruits ye shall know them.
You might not think this verse for instance identifies the pure text, but it does. Look at the fruits of the Alexandrian texts and compare it to the fruit of the Received Text.
So, you may not understand our viewpoint, but we fully believe scripture supports the RT.