Eph. 3:3,6,9 seems to teach this. I'm wondering if the 'body' in view is the cosmic ecclesiastical community only or if particular local bodies are envisioned as well.
"Let me offer some discursive ramblings in favor of considering the racial composition of a church, of thinking about ‘races’ and not just ‘persons’ if I may. This statement stings me: '90 percent of congregations are at least 90 percent one race'. To my mind, this fact suggests that the Christian church, whatever else it is, is not less than racially/ethnically tribal. Empirically speaking, it says that race & ethnicity constitute as much a ground for inclusion in particular local churches as any other factor. We can look at that and say 'fine' I guess. But in light of increasing diversity in schools, neighborhoods, marriages, gov't, military etc., in the face of persistent monoethnicity in churches (still the most segregated hour of the week), many are provoked to ask, 'What's wrong with the church? If the 'mystery' of the gospel, (a la Eph 3:3, 9) is the bringing together into one body, Gentile and Jew (by extension gentile and gentile in our day) and the effect of the gospel mystery is to move us toward deep, self-donating one-anothering (regardless of race/class/gender), shall we be content to allow this mystery to play out at every level but the actual local church level? I’m inclined to answer in the negative. So, why talk about bringing other ‘races’ in to the church and not just ‘persons’? The working out of our new humanity within a new community demands a counter-cultural racial inclusion in the body. This inclusiveness, I would suggest, is more demonstrative within local assemblies than just between them. I am painfully aware of cultural clashing and can only say that patience, forbearance, and love have led to increasing oneness and unity with the racially ‘other’ in my life. I have a long way to go though. One can not be too prescriptive concerning exactly how this should look in every believer’s life of course. Callings are particular and varied. But at the global, north american ecclesiastical level - 90% of churches having 90% one race - is definitely not it wouldn’t you say? I don’t want to have an overly eschatological ecclesiology that insists on seeing the ‘not yet’ completely in the ‘already’. There are obviously limits and qualifications.
I suspect that the monolithic landscape is less a result of intentional exclusion (‘blacks are not welcome here!’) than the unintentional persistence of deeply formed patterns of social relating which we seldomly, self-consciously disrupt in the interest of inviting in the racially ‘other’. In fact, I rather suspect that most churches would welcome greater diversity, say they even want it, but do relatively little in the way of self-denying, discomforting social re-arrangement (again, in the interest of making room for the ‘other’) which might pave the way for inclusion. Would it look noticeably different within most churches if they were intentionally exclusive? 90% is A- grade de facto segregation (B+ at WTS ;-). So many things to say/discuss.........Please feel free to challenge this vigorously" (comments from a previous post)
"To sum up, we may say that 'the mystery of Christ' is the complete union of Jews and Gentiles with each other through the union of both with Christ[cf 3:6]. It is this double union, with Christ and with each other, which was the substance of the 'mystery'."
-Stott, BST, p. 117.
I never thought of union with Christ as having a racial component to it.