For starters I offer: 16All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; 17so that the man of God may be adequate, equipped for every good work. 2 Tim 3:16-17
That does not at all proclaim that no doctrine exists outside of that found in Scripture; it states that all scripture is good, not that all good is only to be learned from scripture.
It would make sense to say of your henhouse, “All the eggs in my henhouse are good to eat for breakfast so that you may have sufficient protein for the day.”
Logically that would be a far different statement to say:
“Only by eating the eggs in my henhouse can you find sufficient protein for the day.”
But for your quote from II Timothy to apply to satisfy my question and prove your claim, it would need to read like the second example above, as in:
“Only scripture, inspired of God, is profitable to teach, to reprove, to correct, to instruct in justice, There is absolutely no other authority, inspired of God, to assist that the man of God may be perfect, furnished to every good work.”
But it doesn’t say that. It does a no better a job of proving your claim than Genesis 3:15 does of proving my claim regarding Mary as hated supremely by Satan, does it? Yet my claim has a better chance of being true because it is backed by the true Catholic (the only - universal) Church.
If that is for starters, do you have anything more verses from scripture that actually back your claim?