This was radical.
“Christianity comes from Judaism, but Jews think they are Chosen People: Only them have been chosen by God to receive the Torah and follow his commandments. It’s a religion mixed with an ethnicity. A private club. Back then, virtually all religions were private clubs.Christianity killed that and declared itself open to all”
https://unchartedterritories.tomaspueyo.com/p/how-christianity-went-viral