The end-time church of God shows an incredible diversity in unity, that is to say, an incredible diversity under Jesus. How diverse should the local church be? Often the local church just doesn’t seem to represent what Jesus has achieved ( #1 Introduction, How diverse should the local church be?). Sometimes, part of this is understandable – you live in a township where, well, there ain’t a white face within 20km, so how do you expect whites to have a real presence in your otherwise completely black church. Other times it simply seems that we’re either being lazy or, worse than that, we’re not actually thinking properly about who God is (#2 God, Diversity in unity under God, a sort of Biblical theology of diversity within the plans of God).
How diverse should the local church be? Actually, what does diversity in unity look like? – what does diversity within the church of God look like? What does it do? How is it used by God? Diversity in the church of God involves at least two things. The first is that it involves space for particularity and God uses it to give us opportunities to love and learn.
Here is the second element, namely that it involves
ii) God on display (and a drawing of people)
One of the major themes in Ephesians is a unity which has been achieved. So, Ephesians chapter 4 verse 2 reminds us that we are to keep the unity of the Spirit with the bond of peace. To keep it, not make it.
This unity which has already been achieved is, surprise surprise, the work of the Triune God. The Triune God stands behind it, and over it. Chapter 1 shows us that the Father chooses, that the Son redeems, and that the Spirit seals. And in chapter 4, Paul likewise situates the church’s unity in the Trinity as he draws our attention to the one Spirit, the One Lord and the One Father of all (vv. 4-6). The very existence of the church displays God and Him at work (cf. post 2).
Chapters 2-3 of Ephesians drive home the complexity of this unity: it involves dirty pagan Gentiles with kosher set-apart Jews. Think about it, we have devout Jews who for ages and ages have been told ‘look, don’t mix with those types!! Don’t!’ And yet now, the kind of unity achieved mirrors marriage language: the two become one (2:15); they are co-heirs and partners (3:6). Really? Not only is the unity that stark, but it is the unity of groups which previously were not allowed to mix. The diverse, even to the point of being enemies are united ‘maritally’ with the peace that Jesus brings (2:15-16). They are harnessed together to be one, co-heirs and partners. Here is the church: diversity in unity through the Son displaying God’s wisdom (3:10) and bringing Him glory (3:21).
We know that it is difficult (a difficulty compounded by our sin) for diverse people to relate and so Paul urges the Ephesians to accept one another in love (4:2). Love is the way of relating. With God revealed to us as Trinity, we should not be surprised that relationships and love are so central. With one another we are given the opportunity to reflect the things that matter. Have a think about the first multiethnic church of Acts 11 at this point. While we’re reading about the church of Antioch in Acts 11, we’re slipped the line that it is here that the followers of Jesus were first called Christians. Go have a look at it. It is a very diverse church, even the leadership is diverse. Why might people have stopped there and gone ‘These are followers of Jesus, these are Christians!’? Well, I must admit that I can’t help but remember Jesus’ words of: ‘By your love for one another will they know that you are my disciples’ (John 13:35). Amidst the obvious difficulties of loving within a multiethnic church, we have God’s relational love on display, highlighting these people as followers of the Jesus who showed us love.
The HUP (Homogeneous Unit Principle – see previous posts), as espoused by McGavran and others, is presented as a missiological tool, in other words it’s meant to help us with the fulfillment of the church’s mission. And it has the aim of having a church in every culture. Much about the HUP makes sense: like reaching like is often easier. People are more likely to interact and respond positively to people who are like them in either looks or interests or speech. But!, there are at least two critiques to the HUP way of thinking.
Firstly, the HUP misses church as an end in itself, not only as a means to an end. God’s church initiated by Him is a group of diverse people loving Him and loving one another. It’s not only a means to getting the church of Revelation 7 when Jesus returns but it’s a great opportunity now for us to see the kind of unity that Jesus brings – people who might not normally hang out, actually being united by their common faith in Jesus.
Secondly, the diverse church should be considered missiological! Bentley Hart’s apt description of the world watching the early church states: ‘Men of high attainment—literate, accomplished, propertied, and free—had to crowd in among slaves, laborers, and craftsmen, and count it no disgrace.’  Diversity which is divided within the world but united in the church, well, it gets people asking questions: ‘What the heck could do that? What could possibly stand behind those people, so different from one another, actually hanging out? No, no. more than that: actually, genuinely, loving one another!’ What they see on display is the kind of love of Jesus which is initiating, personal, and sacrificial.
The Revelation multiethnic church could not help but cry ‘Salvation belongs to our God’ (7:10).
God-willing the church reaching and including all kinds of people, will render the watching world almost unable but to utter the words ‘Truly, salvation belongs to your God.’
For no one else but the Triune God could stand behind the Christian church of diversity in unity.
Go here for the conclusion to the series.
 Here I have no desire to forget the ‘categorical distinction’ for which Husbands lambasts Volf (Mark Husbands, ‘The Trinity is Not Our Social Program’, in Daniel J. Treier and David Lauber, eds., Trinitarian Theology for the Church: Scripture, Community, Worship (Downers Grove, Illinois: IVP, 2009), 121, 123. Cf. Miroslav Volf, ‘The Trinity is our Social Program: The Doctrine of the Trinity and the Shape of Social Engagement’ in Alan J. Torrance and Michael Banner, eds., The Doctrine of God and Theological Ethics (London: T & T Clark, 2006), 105–124.) Instead I am asserting that God is: i) relational even as Knox reminds us that ‘unity is the basic concept underlying the doctrine of the Trinity’ (Tony Payne, ed., D. Broughton Knox, Selected Works, Volume 1: The Doctrine of God (Matthias Media, 2000), 78.); and ii) love (1 John 4:8). This is the God revealed in Jesus and Scripture.
As image bearers we should not be surprised at the importance of both of these. Husbands’ mostly valid critique of Volf’s ‘perichoretic personhood’ as over-realised eschatology (Treier and Lauber, Trinitarian Theology for the Church, 126.), in turn shows Husbands bordering on an under-realised eschatology in terms of his understanding of Christian fellowship now, even given the presence of sin.
 Donald A. McGavran, ‘A Church in Every People: Plain Talk About a Difficult Subject’. Available online at: http://www.worldevangelicals.org/resources/source.htm?id=420
 David Bentley Hart, Atheist Delusions: The Christian Revolution and Its Fashionable Enemies (New Haven: Yale University Press, 2009), 170.