The infallibility and divine authority of the Scriptures are due to the fact that they are the word of God, and they are the word of God because the inspiration of the Holy Spirit gave them.
INSPIRATION and the Bible
The Holy Scriptures belongs to the conception of Scripture that, though originating "by the prophets in many portions and in many ways" (Heb. 1:1), it should yet, in its completeness, constitute a unity, evincing, in the spirit and purpose that bind its parts together, the Divine source from which its revelation comes.
The Book Writing Process of the New Testament: Authors and Early Christian Scribes
What is inspiration? What is involved in being moved along by the Holy Spirit? What is inerrancy? Was Tertius, Paul’s scribe capable in his human imperfection to go without making one single scribal error for 7,000+ words? Did Tertius take Paul’s exact dictation, word for word? Were both Paul and Tertius inspired, or just Paul? Was Tertius more of a co-author with Paul, Silvanus with Peter, Baruch with Jeremiah? If Paul alone was inspired, how does the imperfection of Tertius affect inerrancy? What about Phoebe; what role did the carrier have in the process? These and many other questions are answered herein.