There were a number of competing canons in the first century AD, ranging from the Sadducees' canon (which was just the 5 books of the Torah) to the Septuagint canon (46 books). There was vigorous debate between Beth Shammai and Beth Hillel over the Chronicles and the Song of Songs, and so forth. A twenty-four book canon is mentioned in the Midrash Koheleth.
It's a reasonable inference from evidence that Jesus and His Apostles accepted the full Septuagint canon (46 books), since 85% of the OT verses quoted in the NT are quoted directly from the Septuagint.
Consider the anti-Messianic faction of the Jews led by Rabbi Yohanan ben Zakkai in the first century AD. After the Temple was destroyed they were facing an existential threat, being increasingly challenged by the growing Messianic (Christian) movement. Whether at a hypothetical Jewish Council of Yavneh/Jamnia or elsewhere, Yohanan ben Zakkai and his Halachic School eventually came up with their own OT canon (an anti-Messianic canon) sometime between 90 AD and 100 AD.
This scaled-down canon included 39 books and excluded 34 books. All of excluded books were written in Greek: the 7 Deutercanonicals plus the 27 books we now know as the New Testament. (Whether John 1, 2, 3 and Revelation had been written yet I do not know, but I am including them in the count because they were all excluded by the circa 90 AD rabbinical reaction against Christianity.)
They excluded these books because they supported so directly to the beliefs and practices of the rival Christian community.
The limitation of the TaNaKh to the 39 Hebrew manuscripts, while accepted by the anti-Messianic Jews (Ben Zakkai) was not accepted by the pro-Messianic Jews (Christians) nor by the Gentile converts to the Christian faith.
The Masoretic Text, a very late development, was primarily copied, edited and distributed by a group of Jews known as the Masoretes between the 7th and 10th centuries AD. --- it's the authoritative Hebrew text of the Tanakh for Rabbinic Judaism today, as well as for most of the Protestants.
The bottom line is really what St. Jerome (translator of the Vulgate) said about his final, 46-book OT Canon: "What sin have I committed if I follow the judgment of the churches?"(Against Rufinius 11:33, A.D. 401). "The judgment of the churches." That means he was going beyond his own individual opinion, going beyond the halachic opinion of rabbis who didn't believe in Christ, and going instead with the consensus of the churches who had received the Scriptures from the Apostles, and from the successors of the Apostles, for their liturgical proclamation.
In other words, Jerome could go forward with
He could choose his own self, the Pharisaical-rabbinical tradition, or the Christian tradition. He went with the Christian tradition.
That was the ultimate source of the canon --- the churches' actual liturgical practice (Lex oreandi, lex credendi") which was handed down to them from the Apostles, presumably under the guidance of the Holy Spirit.
Christ said (John 16:13) "When the Spirit of truth, is come, he will teach you all truth." Christ, through the Holy Spirit, through the processes of history, established and protected the canon via the practice of the churches, ratified by Church councils.
St. Jerome (ca 401 AD) finally decided to abide by the Christian Councils. The Reformation-era Bible publishers (16th-17th century) decided to abide by the Rabbinical Councils. I would argue that Jerome made the better choice.
And yes, the Church would necessarily have infallible authority over this.
I rest my case.
Only God is an Absolute Being and can make Absolute Decisions for others. Since man is not Absolute Being he cannot make Absolute Decision for others, not can ant man or council prove that they have made an Absolutely Correct rendering of what goes in and what goes out.
IOW, no council or decree from any man is binding or can be proven to be Absolutely worthy of being the Absolute Truth.
Yes, I personally believe the 27 NT and 39 OT scriptures are inspired, but it is not up to me or anyone else or a council or Jerome to hold up a set of scriptures and say “Here are your inspired scriptures to go by, saints and heretics alike!”
The Protestant Bible has 66 books. It once had 73. The Roman Catholic Bible has 73, but the Ethiopic Bible has 81 and the Greek Orthodox Bible apparently has a few more books they accept as being genuine than Roman Catholics do.
In the end, there are many Bibles, but as the scriptures say, there is “One Lord [Jesus Christ], one faith [in Jesuys Christ as savior] ... one God and Father of all.”
As long as one puts their faith and trust in Jesus it really doesn’t matter what Bible above you believe in, or if one decides to go back and add a book, say the Revelation of Peter, which was universally accepted in the churches at one time.
If they accepted this book back then and made it to heaven, then does it really matter if you go with the Protestant bible, the Roman Catholic, the Greek orthodox or the Ethiopic Bible or add something else that is innocuous (like the Revelation of Peter) as long as you fix you faith, trust and hope in Jesus? No, it doesn’t.
If each of these has a different Bible then who am I to say to someone if they also go with one of these or go along with one of theses along with the Revelation of Peter, shown above to be universally accepted in ancient times.
BTW, I don’t personally believe that the Revelation of Peter is inspired.
I rest my case as well...