Synagogues, Not Chruches
And so James writes a letter to a group of Christian believers and instructs them about favoritism within their "assembly." The word here in Greek is synagogue. Yes, the same word we call an assembly of Jewish people. James didn't write to a "church" because in the 1st century, the church was not a thing. The Jewish believers of Yeshua, along with the newly grafted in Gentiles, gathered in synagogues as Jews did every Sabbath.