The danger of speaking of what Jesus has done in terms of creating a “new humanity” is that it almost always marginalizes the importance of ongoing national, cultural, and ethnic identities in the Body of Messiah, among both Jews and Gentiles, whereas when Paul spoke of the “One New Man” (Eph. 5:15) he simply meant that Jesus believing Jews and Gentiles would no longer experience the same levels of hostility and strife that they commonly did in the first century Greco-Roman world.

In no way does Paul mean that a Jewish person is no longer Jewish or that one’s national background is irrelevant in Christ. In fact, it is the maintenance of one’s national and cultural identity, in submission to Christ of course, that brings Jesus the most glory as King of Israel and the Nations. - Travis M. Snow