The early church began to speak of Christians not as Jews or Gentiles but as something new — a "third race" alongside Jews and Gentiles.
I understand the logic behind this and there is perhaps a sense in which it has some truth. However, on the whole I find the notion unfortunate and unhelpful.
I will not develop the case for this here but will simply assert my understanding of the issues. If that is of any merit to anyone then great. If not, fair enough.
It seems to me that speaking in terms of biblical theology there is not a third race. There are Jews and there are Gentiles. There is no third category.
Christ-believers that are Gentiles when they are united to the Messiah do not cease to be Gentiles;
Christ-believers that are Jews when they are united to the Messiah do not cease to be Jews.
What they are is Gentiles in Christ and Jews in Christ.
What they are is Gentiles and Jews eschatologically transformed in Christ.
What they are is Gentiles and Jews united as one body in the Messiah.
BUT they remain Gentiles and Jews.
Of course, we all know that "in Christ there is neither Jew nor Greek" (Gal 3:28) but this should not be understood to indicate that all distinctions between Jew and Gentile are removed in Christ. If they were they there would be no differences between men and women (on the basis of the same text) and that would really mess up things!!! Yes, salvation and receiving the Spirit do not depend on whether one is a Jew or a Gentile — in Christ, there is no difference. But that is a different proposition from the eradication of all distinctions between Jew and Gentile identities.
So I think that we should avoid talking of Christ-followers as "a third race" — much better to conceive of the ekklesia as a body of eschatologically renewed Jews and Gentiles united to the Messiah by his Spirit. Our Jewish and Gentile distinctives remain (as do all the wide variety of distinctives between different Gentile ethne).
The unity of the body of Christ is not uniformity but a unity that holds together great variety.