Apparently I am missing the point. Or you are. One or the other.
It appeared that you were saying the book of James could not apply to gentiles.
If it were written to CHRISTIAN Jews, how could God/Christ apply different commands to CHRISTIAN Gentiles? Or should I say, nullify certain commands to CHRISTIAN Gentiles?
'for there is neither Greek nor Jew, slave nor free, male nor female, but Christ is all, and in all.' ( I don't know where it is at the moment for complete accuracy, but we know what scripture I am referring to.)
a God of all truth, who has to SAME Spirit abiding in us, does not differentiate. That would be partiality. But not only that, it would be sin! If we know these truths by reading James, we now have a truth revealed to us, and going against that truth is sin! God clearly says He shows no partiality. 'for there is no partiality with God.' Romans.
So as in James, Jews cannot show partiality to the Rich man who comes into there assembly, but Gentile can? Or only Jews must be quick to hear, slow to speak and slow to anger? Well, I assume you get my drift.
Even in the Old Testament, the same laws applied to the aliens among them. God said that several times. (Except for a few regarding the temple, because that would be defiling the temple, in which Christ has taken away and nailed it to cross).