Season's greetings folks, lets not forget the council of Nicea in 325 AD, which Constantine organised to get the messy collection of ideas in the "Christian" Mystery religion into good Roman order.
By this time Christians made up most of the civil administration of the Roman Empire and persecution was no longer an option without paralyzing tax collection, so Constantine came up with the idea of fusing Christianity with Mithraism another mystery religion. Now Mithraism was the religion of the legions, so by combining the two he got the Army and the civil service batting for the same side.

Mithras

This of cause is not just true of the "New Testament" but the rest of the Bible was begged borrowed or stolen from other cultures; it's monotheism and concept of a Messiah from Akhenaton's Egypt, it's flood story from Babylon and lots of other ideas from the Canaanites.

Have a good New Year

PP