We have been discussing the development of the Christian scriptures and the theology they contain on another board where I post.
One of my best friends, who is a physicist has a real way with words. This is his take on how the present theology developed. From all my reading, agree with his take:
"I think one of the reasons for such a broad range of beliefs is that the origins of Christianity had two very different sources with very different messages. Jesus proclaimed his message to Jews. His focus was on the redemption of Israel and the establishment of God's kingdom on earth. To Jewish ears, and I am sure in the mind of Jesus, this was to restore Israel to its previous national independence and free from Roman rule. The time was ripe for God to intervene in history and this imminent event was to be accomplished by miraculous overthrow of the wicked by the army of God's angels coming in the clouds. The Jewish peoples responsibility was to personally repent and live exemplary lives of righteousness. Thus this is a dual message of a call for extreme personal righteousness with a focus on love for God and fellow man and an extremely violent message of wholesale slaughter of the wicked.
On the other hand Paul was preaching to an entirely different population who were Gentiles who had a very different world view. They too were living in a Roman dominated culture and were saturated with Roman gods and what we call pagan worship. Paul's focus was on personal salvation. For him the enemies of this world were not the Romans but 'principalities and evil spirits' who were vying for the souls of mankind. Paul saw the crucifixion in the light of both the Jewish and pagan sacrifices made to gods. The resurrection was vindication of God's acceptance of the sacrifice of Jesus and acceptance of those who would acknowledge him as saviour.
From these disparate beginnings the various groups of followers managed to interface, but not too harmoniously. Luke tried his best to paper over the divisions of these basic differences with the stories of Paul visiting James however underneath his stories one can see the more vehement division. As the church became consolidated under Constantine's desire for a monolithic church to support his unified empire there developed a forced consensus and what we have inherited today in the melded theology which in many cases does not sit well with anyone who tries to rationalize the various elements forced to fit together."