I was discussing with a friend yesterday how common religious relativism has become among conservative and liberal Christians. No, I mean that seriously. Christian unity is important; indeed it is imperative. It is a good and right thing for Christians to engage in conversation, friendship, and common mission across denominational and confessional lines. However, there are really unhealthy ways in which to talk about it.
"I'm a Baptist, because that's what I think is right for me. I'm glad that you're a Methodist, because that's what God has called you to be. It doesn't really matter because we all love Jesus."
Such sentiments mean well, but they are problematic. While beauty may be in the eye of the beholder, truth is not. God may very well call people to build their lives in particular denominational traditions, but I believe that if Jesus is faithful to his own prayer for unity in John 17, the trinitarian God has a trajectory in mind for all churches, that at least in the eschaton, we'll all be one. The way to build such unity is not through relativism.
When I say, it's good and of little consequence for me to be a Baptist or Anglican or Lutheran, and I say the same about your affiliation as a Pentecostal or Catholic or Methodist, I might be playing nice, but I am not being respectful. When I downplay the significance of such things, I also deny the value of those traditions.
If I am to say that the Baptist tradition has something real and meaningful and important to offer the rest of the Church of Jesus Christ, I must first say that it is of some significance for folks to be Baptists. If there is anything good in a tradition, I must first say that it matters.
Would it surprise you to hear me say that I am an Anglican Christian because I think it is the most faithful way, in this time and place, to respond to and embody the fact of God's reign in Christ? If I believed otherwise, I would certainly go and do something else. I would certainly be surprised to hear a friend confess that they did not believe their tradition to be a more faithful way - otherwise, why would they be involved as they are? However to say this is not to say that other Christian traditions are not faithful - such binary thinking gets us nowhere, and is as uncharitable as it is untrue.
I only treat my own tradition with integrity when I say that it matters that one is part of it, and that it offers particular gifts for Christian faith and practice, and that - heaven forbid - people should get on board with it.
When I can say this, I can then dialogue critically with other traditions: I can learn them, and receive the challenge they offer to my own, and how I live and understand the faith, and offer challenge to them in return. I can acknowledge the ways in which they can teach me to strive toward a move faithful obedience to Christ, and be warned away from pitfalls. If I also believe such things matter, they can learn from me and criticize me as well.
My point? We don't have tell ourselves that our differences don't matter in order to play nicely together, and it's only when we know that our differences matter very much that we can learn from one another.