Unity is a puzzling concept for me. For one thing, it is bound up in identity, and unfortunately it's rather hard to think about identity without subtly (or not so subtly) bringing in Plato's forms. The scenario is familiar. Plato used the example of a chair (therefore I feel compelled to do so as well). We can't call two four legged objects, which happen to be designed expressly for sitting, chairs unless we grant that there's something they both share which makes them chairs. So, we attempt to nail this attribute down. The more we talk about it the more abstract it becomes, and finally we've stripped all of its particulars away and we're left with a universal. By the way, if a better mind than mine can think up something to call this besides "chairness", I would be most grateful. Now we can be Augustinian and locate this in the mind of God, or we can be more traditional Platonists and allocate it to some ethereal region (but let's not). So much is familiar to anyone who has taken an introductory Philosophy course (I have, by the way, and therefore am now part of a minimally exclusive club of people who know everything about it.)
Christian unity, and Christian identity, does not operate in this way. I do not share an ethereal "christian-nes" with the citizens of the City of God. Paul instead uses one particular phrase over and over again. He uses this phrase especially in Ephesians to locate the identity of the believer. This phrase is "in Christ." For example, in the opening verse of Ephesians he states that he's writing to the faithful in Christ. In v. 4 he says "as he chose us in Him (i.e., Christ)." It is this trait, being in Christ, which unites me to all believers. We could talk more about what the implications of being "in Christ" are, but notice that it is no longer abstract. Unity for believers is not bound up in some trait which is itself located in an ethereal realm of the forms. It's not even something located in the mind of God. It turns out that unity is bound up in a person. The person of Jesus Christ.
In the past, I've been distressed by the diversity which I see in the church today. The thought of thousands of different denominations seemed to me, like a great evil. This was especially apparent to me considering that, in the not comparatively distant past (I'm talking about before the East-West split), there once was only one true church. I may have even taken sides with Chesterton in my frustration, when he seemed to take jabs at protestants for messing it all up. To him, Protestants might be part of what's wrong with the world. My thought is, surely Christ would want there to be only one church which worshipped him.
I get an immediate, "no" answer in Luke 9:49. The disciples came running like tattletales to Jesus with the appalling news that men, who were not with the disciples, were casting out demons in Jesus' name. Jesus gives an ecumenical answer, "Do not forbid them, for he who is not against you (all) is for you (all)." This answers two types of people (who are really quite similar). First, it answers those who, like the disciples probably, are more interested in gatekeeping. We need to stop them because they haven't been with us. Secondly, there are those (more like me) who wish that all these churches would just agree on what the Bible teaches. I did not think of this sentiment as anti-ecumenical until I heard Pastor Douglas Wilson explain it in a sermon. The thing is, it's an excellent sentiment. But what it really means is that I wish everyone would agree with me. After all, I have the advantage of being right.
The complete picture of what true unity is in Ephesians 4, "[There is] one body and one spirit, just as you all were called in one hope of your calling; one LORD, one Faith, one baptism, one God and Father of all." This is true unity. Paul continues in v. 11 to explain the need for apostles, prophets, evangelists, shepherds, and teachers. They are a gift to equip us all for building up of the body of Christ, to grow us up into maturity so that we are no longer led astray by every new doctrine. In the end, if I were to reject the church because it is supposedly disunited I would be cut off from the very body to which I am called to be united. Besides being sad and lonely, the church of Rob Noland would be composed entirely of hypocrites.
NB: I have borrowed heavily from the work of Mark Driscoll in his excellent book, "Who Do You Think You Are?", which is essentially an exposition of Ephesians.
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