I agree the concept of second (but lesser) God was already known among Jewish mystics and philosophers when Christianity started. I also agree it was a direct influence when NT was written. But this doesn't mean it was also originally taught by Jesus and the twelve. Was it just ascribed to Jesus? I mean NT wasn't written by Jesus or his illiterate desciples. It was written in Greek by some educated people.
Good point raised there, we honestly don't know for certain
what Jesus taught about himself.
What scholars
can say with confidence, however, is that soon after his death - in the 30s CE, in the circles of the people who had originally known him - the belief emerged that he was this "
lesser YHWH" and that he had personally been pre-existent with God before creation as his agent of creation and revelation (in this, they associated him with the Wisdom &M referred to as God's creative agent in the sapiential literature, such as Proverbs, Sirach, Wisdom of Solomon).
The baptismal creed cited by Paul in 1 Corinthias 8:6 ("
yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist") and the christophanic hymn in Philippians 2:6-11 ("
who, though he [Jesus] was in the form of God, who did not regard equality with God as something to be exploited, but emptied himself, taking the form of a slave, being born in human likeness") are 'quoted' by Paul as pre-existent traditions that were already known to his audience in the 50s CE (i.e. they needed no elaboration, their truth claims are just presipposed), so scholars such as Hurtado, Ehrman, Bauckham, Fletcher-Louis and Boyarin are convinced that this belief in Jesus's exaltation/glorification to the heavenly realm and corresponding pre-existent divinity, had been taught by the early church soon after Jesus's death.
Why this belief about his status emerged in the circles of those who had actually known him - and taught Paul - is disputed. Hurtado thinks it stemmed from post-resurrection 'mystical experiences' like that attributed to the deacon Stephen in
Acts 7:55-56 ("
But filled with the Holy Spirit, he gazed into heaven and saw the glory of God and Jesus standing at the right hand of God. “Look,” he said, “I see the heavens opened and the Son of Man standing at the right hand of God!”)
There is a binitarian formula to all of these early 'visions' and we know from Rabbinic literature in the Talmud that other Jews of this period - including a Rabbi of note, Elisha ben Abuyah (born in Jerusalem sometime before 70 CE) - also had visions of the divine
merkabah (throne) in which they reportedly claimed to see 'two divine figures' (the God of Israel and his 'agent', in ben Abuyah's case 'Metatron', the lesser YHWH seated beside him on a throne) and thus fell into a form of Judaism that the Rabbis regarded as "heretical".
Consider
Hagiga 15a in the Babylonian Talmud, which explains how this Rabbi Elisha (referred to disparagingly as 'aher' the "outcast" for his lapse into binitarian heresy):
Four men entered the pardes — Ben Azzai, Ben Zoma, Acher [that is, Elisha], and Rabbi Akiva..Aher chopped down the shoots’: Of him the verse says, “Do not let your mouth cause your flesh to sin” (Ecclesiastes 5:5). What does this mean? He saw that Metatron had been given permission [תושר] to sit and write the good deeds of Israel. He said, but it is taught that on high there will be no sitting, no conflict, no “back,” and no tiredness! Perhaps, G-d forbid, there are two powers [יתשתויושר]!
So, we know that his 'merkabah mysticism' ultimately led him to join one of these binitarian Jewish strains in Second Temple Judaism - specifically the Enochic-Metatron one that appears to have produced the
Similtudes of Enoch and some of the early
Hekhalot literature.
This same binitarian theology is attested in a number of the Dead Sea Scroll texts from Qumran dating from the first century BCE, such as the Melchizedek scroll (11q13) and the Self-Glorification Hymn. These were earlier Jewish sectarians unrelated to the strain/sect that produced the Enochic-Metatron texts. So there seems to have been quite a few of them across a wide geographical spread, with early Christianity being yet another of these 'sects' to have emerged in the Second Temple era (albeit, ultimately, by far the most successful and enduring in the long-term).