The topics of authority and inspiration go hand in hand.
That is true. Let me amplify what I think is meant by that.
Paul's letters are authoritative, not because he was taking dictation from the Holy Spirit in writing them, but because he was an Apostle. A true Apostle. Full of the Holy Ghost and power, called of Christ directly, and taught by Him directly. Not a mere messenger or representative, but truly a vicar of Christ. Not all his letters of instruction made it into the canon, not because they were less authoritative than the ones that did, but because the ones that did were copied more and circulated more widely, probably because of a more universal application to the churches world wide, resulting in their preservation.
By the authority of his office, his letters to the churches are the words of God, and any reliable copy or translation thereof, bears that same authority, despite variations in readings due to translation and despite copyist errors, and is therefore the 'word of God.'
I'm talking about the New Testament, of course, and specifically about the apostolic epistles and Gospels. Revelation may have some dictation in it, as in the letters to the churches, but it is mostly descriptive of a vision. John was told to write down the things that he saw, he wasn't told to use certain words, and the Holy Spirit didn't take control of his pen.
And then there are the synopses of Mark and Luke, which, if there is such a thing as derivative authority or inspiration, then these Gospels derive their authority from the fact that Mark and Luke were close associates of the Apostles, and may have even carried the title of Apostle themselves. They definitely had a good report of the Apostles, and some think Paul was quoting from Luke's account when he said the "laborer is worthy of his hire."
Regardless, their Gospels were copied and widely circulated among the churches as well as Matthew's and John's, again, resulting in their preservation. It's obvious their Gospels were recognized by the church as the truth about Christ, and therefore carried the authority of the 'word of God.'
Now the question is Do you believe the Bible you are holding in your hands is the "Word of God?" Why or why not?
Yes, I see it as the final authority in faith and practice, embossed with the seal of the King of Kings. In other words, bearing His authority, as if He moved the pen on the paper Himself, because it is a reliable translation of copies of the originals.
The Word of God is a Person. The Bible contains the words about the Word.
The Truth is a Person. The Bible is the truth about the Truth, but not the Truth Himself.
Scholarship and the comments of preachers and teachers are the truth about the truth about the Truth, but not the truth about the Truth itself.
This parsing is not mine. It's a variation of how a Lutheran preacher, who had suffered 14 years in Communist prisons in Romania for the Testimony of Christ, said it once. And I can't think of a better way to say it.