I'll probably take some heat for this, but I think the above is pretty much bull and demonstrates the hobbled American evangelical semi-dependence on German historical-critical methodology, swallowing the German historical-critical presuppositions hook, line, sinker, while at the same time denying 100% the consequences of doing so. The problem is that "verified apostolicity" as a prerequisite for inspiration is a slippery slope that leads to liberal theology, which I define as treating the Bible as any other historical document that merely contains godly, spiritual insights and maybe even "God's Word," but only if you can distinguish these, with the use of critical methods to be sure, from all the fallible human elements.
Beginning with Johann David Michaelis, we have the idea that "most" of the NT books had apostles for authors and therefore were inspired. But Mark and Luke/Acts, though sanctioned by Peter and Paul, were not to be seen as inspired and written with supernatural help. If Hebrews was not by Paul then it would only be an excellent letter and not inspired and inerrant. So the division between inspired and uninspired books within the Bible already begins with Michaelis. Johann Salomo Semler develops the idea further with the division between the "Word of God" and the Bible. For him, many things in the Bible are not the Word of God, the Jewish OT and Christian NT canons were put together completely arbitrarily, and therefore not all the books within them could have been inspired.
You can keep on the above line of NT development thinking with Johann Philipp Gabler, Ferdinand Christian Baur, Heinrich Julius Holtzmann, Gustav Krüger, William Wrede, Adolf Jülicher, Werner Georg Kümmel, Philipp Vielhauer, etc., but what's the use? And what about the OT? We know nothing for sure of the final authors. Even the Pentateuch had someone after Moses with his hands all over it, cf. e.g. Deut 34 and esp. 34:10, which demands someone long after Moses commenting in retrospect. And what of the other books? We know nothing for sure of their authors, not to mention all the times of apostasy and reckless abuse or disuse of the Scriptures by the "official" Jewish religious leaders, from whom much of our current documentary evidence derives.
All of this leads back to the principle of faith, already mentioned in this thread, that God inspired men, usually those despised and rejected by "organized" Jewish and Christian religion, to write down his very words and to group them and then deliver them as a deposit to God's people. Leaders of organized religion bickered and fought (and still do) over what should and should not have been included, but try and fight as they may, they couldn't undo one bit what God through the Holy Spirit did and settled for his people for all time.
Sincerely,
Jonathan C. Borland