Where does it say so? I'm looking for evidence. I'm asking for documentation.
Hmmmmm. Interesting. Before going any farther, let's start with the verse I quoted, Isa. 8:20. What does that say to you? What does it mean to you practically?
As it as sic the Church that said it was the Word of God.
If you are referring to Laodicea??? for example, whether the Church at that juncture were to have said it was the Word of God, or not, it would still be the Word of God.
It's also Tradition that the Gospel of St. John is written by St. John.
That information may also be derived from the Bible itself, tradition be what it may or say what it may. Although, the identity of the author is not material to the inspiration of the book.
Tradition also brings us the the definition of the Trinity.
Not the Bible doctrine of the trinity. The Bible very clearly teaches the Trinity. I should point out that the RC doctrine is different in some respects than what the Bible teaches.
It brings us the definition of the person of Jesus.
That is found, and stated, very, very plainly in Scripture, without any reference to any church's tradition.
Where is the evidence for this? Where is the documentation?
Very well. If this is a concept you are not familiar with, then I should be glad to make an effort to assemble relevant Bible passages for your benefit. That will, however, take a bit of time, and it is rather late at the moment.
That's not what the Scriptures say
15 So then, brothers, stand firm and hold to the teachings we passed on to you, whether by word of mouth or by letter.
Paul is here referring to his initial teaching, which was by word of mouth, and his subsequent letters. He is admonishing the believers to not stray from those teachings. He also warns that a falling away would come, and urges that the church stay faithful to what they were originally taught.
I'm asking for basis and documentation.
As I understand it, you are asking for Biblical passages that state or support the concept of the all-sufficiency of Scripture for the knowledge essential to salvation. I am assuming here that you are not familiar with those passages, for if you were, then presumably you would not be asking for them. And I have compiled a study on this point. I will have to dig it out and see what I can do to answer your question. May take a bit of time.
Dave