"I pray that they will all be one, just as you and I are one..." John 17. 21
Does the unity of the church where you are advance God's Kingdom or contradict it? Does the way we relate to fellow Christians (and they to us) confirm or deny our message of reconciliation? You see it mattered enough to Jesus that he put Christian unity at the heart of his high-priestly prayer. It's the "new commandment" he gave his disciples: Love one another as I have loved you" (John 13. 34). And it's what he said would be the foundation of our witness to the world. So how are we doing?
The fact is that the church is riven with division. The rot set in early. In his first letter to the Corinthian church, Paul tears a strip of his fellow believers for dividing into rival camps: "One of you says, 'I follow Paul'; another, 'I follow Apollos'; another, 'I follow Cephas'; still another, 'I follow Christ.' (1. 12). His riposte is to remind them that Christ alone died and rose for them: not Apollos, not Cephas, not Paul himself, nor anyone else. And it is on that basis that we find our unity today.
We cannot be held responsible for the accidents of history but we shall be held accountable for how we conduct ourselves going forward. The existence of so many churches and denominations, many in open rivalry of one another, makes us all look ridiculous and, when we preach reconciliation, we sound like hypocrites. And it's no good hiding behind pious platitudes like "we are all united in Spirit". That's like saying "it doesn't matter what I do in the body because my soul is going to heaven". For Christ's sake and for the sake of his church, we must make what is apparent to the world consistent with what we profess to believe. Christ is Lord of all, therefore we must obey him with all of our lives, inwardly and outwardly.
We cannot force unity on those who do not wish to be (re)united but we can make every effort ourselves. To begin with let us resolve never to speak ill of fellow Christinas or another denomination, even when we find ourselves taking issue over a matter of doctrine. Next we can make a habit of consulting our neighbouring churches whenever we are considering any form of outreach, with the intention of working together. And let's follow the Lord's example and put that "new commandment" at the heart of our praying too...