The Bible reflects accretions over a certain span of time.
By 'accretions,' I mean layers of transitional beliefs superimposed
over each other.
In earliest Christianity, there was mostly Messianic Judaism. Gradually, the pagans who converted (i.e. Gentiles) were absorbed--especially after AD 70. In that space of time the strict monotheism gave way to a light paganization (is that a word?) due to Greek influence (demi-god status). In other words, don't be misled into assuming the Scriptures TEACH ONE WAY and one way only. The Scriptures are a diversity of opinions redacted (and forced) next to each other.
So what?
So you can prove contradictory things by cherry-picking carefully. There is no GESTALT.
Christianity is a patchwork quilt.
Of course, the Bible contradicts itself. You have to be purposefully dull-witted to insist otherwise--and you obviously are not that.
Think of it like this.
What if you asked, "What is the ONE reason for all traffic accidents?"
See what violence that context-forcing does to a "true" answer?
Expecting internally inconsistent opinions to be consistent is a wrongly based presupposition on your part.
Welcome!