After reading Christianity isn’t the point, I’m wondering if this whole thing isn’t just a question of semantics. Aren’t Christians the ones journeying and turning toward the Kingdom of God, being transformed by encounters with Jesus? Are you just using new language – “Kingdom” instead of “Christianity” – so Christianity sounds more inviting to Muslims and non-Christians?
We believe that shifting our focus from Christianity to God’s Kingdom is more than just a shift in terminology. Instead, it’s a paradigm shift in how we view our faith, the community of faith, and our relationships to those around us – both Christian and non-Christian. It is a shift that begins to challenge the age-old question of who’s “in” and who’s “out,” one that we’ve found both reflects the complexity of reality & is the most faithful way of reading the Bible and following Jesus.
To illustrate this shift, we’ve found a couple diagrams to be profoundly helpful. 
The first we call a “bounded set.” As Christians, the thinking we often fall into is “bounded” – it’s defined by a boundary. Picture a circle: in it are some dots, and outside it are a few more. In this model, the solid line of the circle that divides the two groups is Christian doctrine, beliefs, practices, etc. – so that all inside the circle are the Christians, and all outside are non-Christian.
One great thing about this way of viewing the world is that it’s black and white – there’s in, there’s out, and I have a nice big boundary line that removes all ambiguity. I love simple stuff like that. However, there are some negative implications of this model when it defines how we think about our faith and relationship to others:
1) Energy. What effect does this way of thinking have in our pursuit of Jesus (discipleship)?
Everyone in this model is a dot or “pin.” Both are inherently stationary. On maps, a pin is a destination – you do all the work to get to that pin, and once you get there, you’ve arrived. In terms of our faith, we are theoretically always disciples and know that we need to grow and mature – but once we believe we’re part of the set or “in” (i.e. inside the boundary of Christian doctrine and practice), there’s very little incentive to “go” anywhere. Instead of “seeking the Kingdom,” knowing we’ve made it, that we’ve arrived, can stagnate our walk with God and our discipleship journey with Jesus. Instead of “seeking first the Kingdom,” we feel as if we’ve arrived (enough).
2) Focus. Where is our attention?
One great benefit of this model is that it clearly shows the community of faith. Everyone inside the boundary is together in one fellowship, worshipping as the Body of Christ in the world. In order to define this community, however, we must focus on a boundary, the big, bold line that separates “us” (the faithful) from “them” (the unfaithful, the “lost,” etc.). By implication, then, our focus in this model is what divides – what can be disagreed upon – a very natural tendency, by the way (consider denominational divides, like the classic tension between Baptists and Methodists).
3) Relationships. How do we relate to others?
We relate well to those who are like us, who are also inside the boundary, who agree on Christian doctrine, practice, and values, as we understand them. But this boundary tends to create adversarial relationships between those in and outside it. It’s like cliques in high school – you know if you’re in…and you definitely know if you’re out. People can feel when we think this way, when there is a solid-lined boundary between “them” and “us.” And it doesn’t feel good.
Bounded sets are a product of Enlightenment thinking. We in the West understand the world in terms of categories, in which a person or thing is defined as part of a category based on its own characteristics. For example: if a something is red, yellow, or green, it grows on a malus domestica tree, and when squeezed produces apple juice, then you’ve probably got an apple in your hands. An apple by definition can’t be 70% apple and 30% pear (genetic modifications aside) – it’s an apple. That’s just what it is.
In the West, we “categorize” all sorts of things, people included: according to Meyers Briggs, I (Stephanie) am an INTJ; on the Enneagram, I’m a 1; on the DISC, I’m a CS. I have to admit, I love categories. They’re so tidy, measurable, predictable (well, I am an INTJ!).
However, pre-Enlightenment (pre-18th c.) and in many parts of the world today, this is not the way people understand the world. Instead of categorizing according to characteristics, a thing is defined by its relationship to what is outside of it. We find this all over the Bible, actually – we are defined by relationships, not by who we are or anything we’ve done. We are adopted sons & daughters of the Most High God, redeemed and set apart because of our relationship to Jesus.
This alternate way of viewing the world is what we call a “centered set.” Picture a big red X. Now envision lots of arrows around the X – some pointing directly to it, some not, some close by, some further away. All have an “orientation” or relation to the X. If the X is Jesus (or the Kingdom of God he embodies) and the arrows are his contemporaries we read about in the Bible, we can begin to tell a story. An arrow quite close to Jesus but pointing directly away from him is a Pharisee – he believes most of the right things and looks like a righteous guy, but he also wants to kill Jesus. An arrow quite far from Jesus but pointed directly towards him is a tax collector, leper, or prostitute – they’re labeled as outcast, unclean, or marginalized, but they dine with him and hang on his every word. Many other arrows are Jesus’ disciples. They try to be close by and oriented toward Jesus…but, well, they’re kind of all over the place.
When we fast-forward 2,000 years and Jesus stays as the X, but we are the vectors, we find some interesting implications of this model, as well:
1) Energy. What is the effect on our pursuit of Jesus (discipleship)?
Everyone is not a dot, but an arrow – a vector. If you’ll remember middle school math, a vector is defined by its direction, or where it’s headed. There is no room for stagnation or complacency for vectors, because they are always moving somewhere, or in this case, toward someone. Depicting people as vectors captures what the Bible talks about with “repentance”: to repent is to turn, to reorient the direction of our lives toward God again – toward that center.
2) Focus. Where is our attention?
The most important part of this diagram is the big red X, the center of the diagram – Jesus. Everything revolves around it, every vector is defined by its relationship to it: every vector is pointing toward, slightly toward, at a tangent, or away from that big red X. It is a “centered” set. So rather than focusing on the boundary (the minimal requirements to “get in”), the focus of our lives in this diagram is Jesus and how we can follow him.
3) Relationships. How do we relate to others?
In this model, there is no boundary to divide and categorize people as “in” or “out.” Instead, since we are all defined in terms of our direction, everyone in this model journeys with and alongside one another. There is ample room for mutual dialogue, to learn from one another, to reorient together toward Jesus and God’s reign, which he embodies.
Christianity, because of its nature as an institution, tends to promote “bounded-set” thinking, but we believe that a “centered-set” mentality is both a more faithful and more realistic representation of our faith and the community of faith. We may feel like we’re stationary at times, but in reality, we are always growing and changing: we’ll have a season when we’re starting to turn a bit away from Jesus, then we’ll turn back toward him (repent) and try to follow him and his way. (Then we’ll do it again.) Our orientation is always changing, however small the degree – we’re vectors, not dots. Although allowing boundaries to define our lives and relationship to God is a much easier task than centering our lives on Jesus, Jesus challenges us to “seek first the kingdom” (Matt 6:33).
So what does this all mean?
By viewing faith and others in terms of a “centered set,” we recognize that Christians don’t have a monopoly on journeying towards the Kingdom of God or being formed/transformed by encounters with Jesus. In fact, some people who self-identify as Christian might even be oriented a good deal away from Jesus, while people who don’t call themselves Christian might be headed straight towards him. It is not just a question of semantics, then – “Kingdom” is not synonymous with “Christianity.” In fact, Christianity is not really the point at all. The central focus is the Kingdom of God embodied in Jesus, and everyone is invited to journey towards it, being transformed by God’s spirit to become part of it.
This is not universalism. God knows those who are His and is more than capable of sorting out those being transformed by Christ. We, on the other hand, “see in a glass dimly” (1 Cor 13:12) and are repeatedly admonished not to judge (Matt 7). (Maybe this is why Jesus told us to let the wheat and tares grow up together so we don’t uproot some wheat [Matt 13:24-30].) God will judge, but the messiness of a centered-set model captures our messy experience of life – it’s not clear-cut to us who’s being transformed by encounters with Jesus and the Holy Spirit! – and gives us a bit more humility to simply journey with others toward Christ and his Kingdom rather than judge who is inside the boundary and who is out.
Paul tells us that we are called to “be transformed by the renewing of our minds” (Rom 12:2). Jesus talked a whole lot about the importance of what happens between our ears, too – not only what we do with our actions, but what goes on in our thoughts: Don’t just not commit an affair; don’t even lust. Don’t just not commit murder; love your enemies. So how we think about our faith and our relationship to others, both Christian and non-Christian, is profoundly important. And when we begin to think about our life, faith, and community in terms of centered sets, we are in a much better position to actually begin following Jesus by building bridges with people who are marginalized and outcast – just like Jesus did.
So if Christianity really isn’t the point and we can’t judge clearly who is in and who is out, then what does it look like to follow Jesus passionately and faithfully with people around us, especially those who believe or live very differently than we do? Read more here: Jesus & God’s Reign
 Paul Hiebert, a Mennonite anthropologist, first coined the terms “bounded set” and “centered set”, which we’ve found incredibly helpful as we’ve thought through our relationships with people of other faiths or no faith at all. See Paul Hiebert, “The Category ‘Christian’ in the Mission Task,” International Review of Mission (Vol 72, Issue 287, pags 421-427), July 1983.