You are mistaken...And God layed it out so a 12 year old could understand it...
2Ti 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
2Ti 3:17 That the man of God may be perfect, throughly furnished unto all good works.
ALL scripture is given by the inspiration of God...And we are to use the scripture as the standard by which we judge Christian matters...
When it comes to another religion, or someone deviating from the Gospel of the Grace of God, tradition, private revelation from God, apparitions, etc., we are to chew the person out, correct the person with scripture and then instruct the person in the ways of righteousness...
And by this correction from the scripture, a man will gain perfection while being completely, thouroughly furnished unto all good works...
The scripture is what it takes, and all it takes...
Nothing I'm saying disagrees with that. Notice what the passage doesn't say. It doesn't say "Only Scripture is given...etc. etc." Nowhere in Scripture does it say written texts constitute the entire corpus of the teachings of God. In fact, the last verse of John explicitly refutes that position.