How did christianity's ethical principles its spread?

I believe the answer is: Broad appeal from the Jews to gentite from rich to poor common man to educated roman

The christianity put more emphasis on how it is harder for the rich to enter heaven compared tot he poor. The appeal that the poor could somehow be 'better' than the rich at something help the religion become really popular among the commonfolks at that time.

in some situations true but in others false