Inserting "all that can be known" for my assertion simply evades the core issue of the dilemma I pose to devotees of Sola Scriptura.
We have in Luke 2 text that clearly tells us Simeon, under the influence of the Holy Spirit, calls the promise made to him God's word. A promise further endorsed by the Gospel writer, himself.
Apart from an OT verse outlining that same promise, the inescapable conclusion must be that all gratuitous assertions claiming that which is NOT in the Bible CANNOT be the word of God, is falsified.
There is no other alternative for those positing the Scripture as the supreme authority in faith and practice.
Further restatement of the rationale that forms the basis of Sola Scriptura is not relevant to the discussion at hand.
I know that is a lot of incoming, but if you read all my response thru, you should have seen that holding to Scripture as the supreme and sufficient authority does not restrict the Word of God to being only written (James White, among others, states that “The Bible is not exhaustive in every detail. John 21:25 speaks to the fact that there are many things that Jesus said and did that are not recorded in John, or, in fact, in any book in the world because the whole books of the world could not contain it.” (http://vintage.aomin.org/cathan.html)
If Jesus said, it, then then it is the word of God, thus claiming that only what it in the Bible can be the word of God is a misunderstanding of the the prima Scriptura or SS position.
However, as i explained, this is not contrary to Scripture being the Divinely established assured Word of God, and thus the supreme authority on Truth, and providing what is needed, both in the clear or the derived sense, for salvation and growth in grace.
In contrast is the position that the church draws its authority directly from God, with whatever sources it invokes for support only having authority because she gave it to them.