Christians were a Jewish sect. These did not have political power, as they were from marginal professions, such as fishermen and prostitutes. The Jews weren't all in agreement as to "eternal life" or the resurrection.
Could it be that the political reality of life, as to political power was what drove their "theologizing"? I believe so.
The Sadducees did not believe in eternal life or the resurrection, but the Pharisees did. Could it be that the Sadducees who were the more "empowered class", as to money and political power didn't need the "promise" of eternal life, because they had more choices as to their life? I believe this is key to how we "psychologically frame" reality.
Christians and the institution of the Church has used Jesus life as their example of Chrsitian faith. Jesus condemned the "white-washed tombs" of the Pharisees because they weren't living their life like he was, as a humanitarian. But, "Christian" was only a term that was useful after the assembling of "like-minded" individuals, a society. It was a way for these to find a "Place of Belonging". They didn't have that choice in the political realities in Rome.
Fortunately, for Americans, our nation values the right of conscience as to choice. This is what supports our diverse climate as to values in life. But, unfortunately, "Christians" don't know their roots, and why the developed theology had "power" over Chruch doctrine. It was a way to make a "better life" without the practical realities of messy politics.