The lessons learned by many in diverse settings around the world have proven time and time again that racial and social reconciliation, even among those who have experienced the transformative power of the new birth, is hard work.  Due to the ubiquitous sinfulness inherent in human nature, the goal of demonstrating the unity of Christ through the structures of the local church will require an intentional effort on the part of its members. According to DeYoung et al., “A church that does not aim to become multiracial almost never does.”  Ortiz adds, “Many urban pastors attempting multiethnic ministries comment that crossing socioeconomic barriers can be even more difficult than crossing racial or ethnic lines.” 
Assimilation or Integration?
A major issue involved in working toward reconciliation is correctly identifying and dividing between assimilationist and integrationist approaches. The assimilationist approach, though often masquerading as the path to biblical reconciliation, fails to take into account (often unwittingly) the power dynamics at play behind majority and minority (or dominant and less powerful) social groups. While proclaiming the message that “we are all one,” what is really being communicated to outsiders is that “you too can be one with us, just as long as you are willing to lay down your cultural and social idiosyncrasies and become one of us.” This, in a way, is similar to the approach of intertestamental and Pharisaical Judaism, which opened the door for Gentile proselytism, but only on the condition of circumcision and cultural assimilation.
Defenders of the HUP have typically portrayed its detractors as favoring an assimilationist approach. According to their line of reasoning, a demand for cultural and social unity within individual congregations of believers carries implicit with it a demand for people to lay down their cultural heritage and conform to the culture of the majority. Wagner, curiously enough, given his usual theological tendencies, has affirmingly pointed to support from liberationist theologians who see assimilationist ecclesiology as a threat to the rights of the downtrodden and oppressed peoples of the world. 
Indeed, if the only choice available were that between pluralist and assimilationist approaches to mission and “churching,” the defenders of the HUP would appear to have a good argument at this point. The goal of true biblical racial and social reconciliation, however, is not assimilation, but rather integration. It involves an acceptance and appreciation of cultural diversity, and a willingness of all parties involved, especially on the part of the relatively socially powerful or dominant majority, to lay down their rights and privileges, and to see things from the perspective of those who are not “our kind of people.” As Piper notes,
This danger is especially present and unseen among majority cultures and majority ethnic groups. When we are in a very large majority, we do not even operate with the category of our own ethnicity. We are just human, so we are prone to think. Others have ethnicity. This makes us very vulnerable to the assumption that God is our God in a way that minimizes his being the God of other ethnic groups. 
Biblical integration is not about obliterating or blurring all cultural distinctives, but rather boldly pursuing unity in the midst of diversity.  The apocalyptic vision of the multitude of the redeemed gathered in unity before the throne of the Lamb is one in which the differences between the various nations, tribes, people, and languages are still perceptibly present.
A Two-Pronged Approach?
Some have proposed that the answer to this dilemma is a two-pronged approach to homogeneity and diversity, allowing for a certain degree of homogeneity in some settings while discouraging it in others.  There are several different variations on this same theme. Some, for example, argue in favor of integration on an intercongregational level, while maintaining homogeneity on a congregational level.  Others insist on integrating congregations, while leaving room for small groups within the larger congregation which are grouped according to cultural or social affinity.
There are apparent merits to the arguments on both sides of this question. Disallowing gatherings along the line of “affinities” (whether along lines of sex, age, race, culture, social class, or personal interests) is fraught with tendencies toward assimilation. At the same time, it may legitimately be asked, what is the qualitative difference between segregation at a congregational and a small group level? Does encouraging homogeneity at the small group level not imply a de facto legitimization of the principle of pluralism as over against integration? Some have argued that both the biblical evidence, as well as the ever looming threat of the human proclivity toward separationist racism, militate against the advisability of homogeneous small groups. 
It would appear that the answer to this question must be tackled on site on a case-by-case basis. To the degree possible, the underlying motives for certain patterns of grouping must be exposed and a way forward that best exemplifies the way of the cross proposed. In the end, it is possible that cultural and social heterogeneity on every conceivable level is not the sine qua non of biblical faithfulness.
In order to achieve the goal of successful integration, several issues must be addressed. One of the most conspicuous is the question of worship style. Not only tastes with regard to music, but also other elements, such as degrees of physical and emotional expressiveness, length of meetings, and patterns of personal interaction are often related to ethnic and cultural backgrounds. In a truly integrated church, there will usually be a blend of different styles, with a growing tolerance of and appreciation for unfamiliar expressions of worship.
Another key factor is a culturally and ethnically diverse leadership team. A congregation whose leadership does not reflect at every level the diversity of its members may almost certainly be presumed not to be following a model of integration but of assimilation. While biblical prerequisites for leadership should never be overlooked,  an intentional effort to promote the leadership of those from minority backgrounds is often necessary.  According to DeYoung et al., “A color-blind approach is not viable since such an approach will likely produce only leaders who are members of the majority group.”  Beyond this, it is crucial that the leaders themselves are good models of racial and social reconciliation in their personal lives. 
An Active Attitude of Reconciliation
Finally, there must be a commitment among church members to actively demonstrate an attitude of reconciliation. According to DeYoung et al., “Most of us need a worldview change to participate effectively in multiracial congregations.”  This change in attitude must be manifest among both the members of the majority or dominant group as well as among the minority or less powerful group: “The importance of dominant group power as a barrier cannot be overstated. The exercise of power is not typically overt or mean-spirited but rather it is done in the name of cultural or theological purity.”  At the same time, those of the minority group may at times feel they must give up something of their cultural identity and heritage in order to fit in with the broader vision of the church. 
Indeed, demonstrating the unity and reconciliation to which God has called us as members of the Body of Christ is hard work. In many ways, it goes against human nature. If we are to be faithful, though, to the vision of radical discipleship inherent in a commitment to follow Jesus, it is not merely an option for the spiritually advanced. While recognizing that as imperfect human beings there will always be room for growth and seeking to avoid a judgmental attitude toward those who may be a few steps behind us in our pilgrimage toward fully understanding the implications of discipleship and putting them into practice, as the church at every level—in local congregations, as well as in missionary strategy and policy driving that strategy—we should manifest a lifestyle of repentance, seeking every opportunity to be faithful ambassadors of the message of reconciliation (2 Cor 5:16–20).
 Kenneth A. Mathews and M. Sydney Park, The Post-Racial Church (Grand Rapids: Kregel, 2011), 185.
 DeYoung et al., United by Faith, 170.
 Ortiz, One New People, 39.
 Wagner, “How Ethical Is the Homogeneous Unit Principle?,” 17. See also DeYoung et al., United by Faith, 117.
 Piper, Bloodlines, 155.
 DeYoung et al., United by Faith, 134–35.
 Ibid., 141–42; Wagner, Our Kind of People, 151.
 Wagner, “How Ethical Is the Homogeneous Unit Principle?,” 18.
 Padilla, “The Unity of the Church and the Homogeneous Unit Principle,” 289, 299; Ortiz, One New People, 143.
 Piper, Bloodlines, 259.
 Ortiz, One New People, 136.
 DeYoung et al., United by Faith, 177.
 Ibid., 170.
 Ibid., 150.
 Ibid., 171.
 Ibid., 114.