Keep in mind what is called Christianity today was not what was practiced back then. The Nazarenes were merely another messianic group no different than others. They didn't believe in Jesus' divinity is the biggest difference which kept them in the ranks of Judaism, not a new religion.I agree, NT wise it looks like Paul tried to share the gospel with everyone he could,
but he said the message was to Jews first.
Then he would go to the Gentiles, when he wasn't making tents and whatnot.
you'd think Christians would get that
in the NT narrative Jesus did at times engage with some non Jews
your point that he preached to non-Christians is true
but his teaching for Believers is is aimed at Christians
I'd see a difference between two.
My view is that James, John, and Paul were all dealing with different audiences of Christians
possibly tailoring their message accordingly and even maybe at times had differing views on some things.
two Christians, 2 and 1/3 opinions (sic)
Then when the Jews died out, apostasy set in... but Paul had initiated this already. Hyyam Maccoby is a good reference.