IMPORTANT: Nobody ever thought they were writing holy scripture!
Any story about Jesus was just as "true" as any other.
But, some groups were more successful at organizing than others.
Think of a political primary with all those candidates pushing their own agenda forward into the public discourse looking for agreement.
Is it always the BEST or the most correct candidate who is selected?
The same process was in force when the necessity of creating an OFFICIAL bible canon emerged!
Powerful lobbyists pushed an agenda forward fully convinced theirs was the best.
The destruction of Jerusalem and diaspora of Jews left only the most rabid and stalwart messianic Jews to slug it out for turf and orthodoxy.
Let's back up a bit.
Get a larger view.
Start at the beginning. Always a good place to start.
There was Judaism before there was christianity. Right? Of course.
The first christians were who? Jews. Messianic Jews. Right? Of course.
That is step one.
You have orthodox Judaism with the Priests, temple, sacrifices, purification rites, commandments, traditions, etc.
Then, you have sects of Judaism.
Why are there sects in Judaism? Different OPINIONS. Different TRADITIONS. Different political views. Different scriptures.
Are you still with me?
Each sect had different arguments and different writings.
The book we now call a Bible was assembled at a point in time each step along the way historically.
The Jews who came back from being captives in Babylon no longer had strict Judaism. Yet, they joined with those left behind and tried
to reform a nation. That nation now had a completely AT-ODDS idea of its own history!
The person(s) putting together an OFFICIAL history of Judaism did not want to further divide anybody. BOTH sets of differing ideas
were put TOGETHER side by side.
When Alexander the Great conquered the known world the Greek influence (and rulership by generals) swept away comfortable views, languages, traditions and self-awareness of tribal people.
The Books of Maccabees make clear the chaos Judaism was plunged into and how it transformed the Jewish world view of itself.
So?
So, by the time the Jesus story started being told (word of mouth) there were hundreds (maybe thousands) of different versions.
Each group, sect, political party would interpret their JESUS as seemed to fit their own viewpoint.
The people who wrote these stories down were no different from any other person writing about God or history.
For one thousand five hundred years there was mostly little effort to provide a readable BIBLE for christians. The CHURCH was more important.
Only when Martin Luther broke with Church Authority was the bible catapulted into the extreme prominence we see today.
Jewish Bible: traditionally 24 books, divided into the Torah (five books), Prophets (eight books), and Writings (eleven books).
Christian Bibles are divided into two parts, the Old Testament and the New Testament.
"Protestant" Bible: the Old Testament has the same books as the Jewish Bible, but numbered and arranged differently, to yield 39 Old Testament books. New Testaments contain 27 books. (66 total)
Roman Catholic Bible: 73 books. Roman Catholic Old Testaments follow an ancient Christian Old Testament called the Septuagint, which includes all the same books as the Jewish Bible, plus seven more. Thus, Roman Catholic Old Testaments have 46 books. Roman Catholic New Testaments contain the same 27 books as Protestant New Testaments. (73 total)
Greek/Eastern Orthodox Old Testaments are slightly longer than Roman Catholic Old Testaments. Syriac Old Testaments often have additional material in an appendix. Greek Orthodox and Syriac New Testaments have the same 27 books as Roman Catholic and Protestant New Testaments. (78 total)
Ethiopian Orthodox Old Testaments are the longest in any branch of Christianity. The Ethiopian Orthodox "Narrow Canon" has the same 27 New Testament books as other branches of Christianity, but the Ethiopian Orthodox "Broad Canon" includes several additional books. (81 total)