Unity in Christ is theologically demanded.
In fact, it could be argued that working to the point of pain and discomfort for the sake of unity in Christ may be theologically demanded by the gospel. Let’s look at a famous passage in Paul’s letter to the Philippians.
Therefore if you have any encouragement from being united with Christ, if any comfort from his love, if any common sharing in the Spirit, if any tenderness and compassion, then make my joy complete by being like-minded, having the same love, being one in spirit and of one mind. Do nothing out of selfish ambition or vain conceit. Rather, in humility value others above yourselves, not looking to your own interests but each of you to the interests of the others. In your relationships with one another, have the same mindset as Christ Jesus: Who, being in very nature God, did not consider equality with God something to be used to his own advantage; rather, he made himself nothing by taking the very nature of a servant, being made in human likeness. – Philippians 2:1-7 (NIV)
In Philippi, things were not all polite potlucks and coffee-fueled hymn-sings. Just ask Euodia and Syntyche, the two female leaders who had worked alongside Paul and Clement but now were not getting along (Phil 4:1-3). Ask those worried sick about Epaphroditus (Phil 2:25-30). Ask those who were disagreeing with Paul (Phil 3:15) or those complaining and grumbling (Phil 2:14,15). Ask those who are going to get the privilege of suffering for their faith (Phil 1:29). The city of Philippi had a church filled with regular humans living in common circumstances experiencing everyday conflict, harmony, and community making. In the passage above, Paul seems to say, that if we are unified with Jesus (or “born again” as some prefer to say), that to make Paul’s joy complete they should be “like-minded, having the same love, being one in spirit and of one mind.” This also is not a call to a cult-like uniformity of thought on all topics or an abandonment of personal opinion or choice. It is specifically that they would be unified in their position of humility and their posture of putting others interest ahead of their own. This unity is a theological mandate because in our relationships with our sisters and brothers we are to imitate our master’s mindset who put our desperate need ahead of his own well being.
Over the last couple of decades I have been in two churches that have sister churches and ministries that rent or share facilities. This has never been easy, but it is always rewarding. In every situation, it is always clearest what our own preferences and needs are. My needs always seem reasonable (to me). My preferences often feel more like the only rational possibility until I meet the knuckle-head who cleaned the kitchen WRONG AGAIN! (Emphasis only in my head, I promise.) When four different languages are singing praises to God every Sunday in a church building people tell me, “It’s just like the banquet table in John’s Apocalypse (Rev 19:18). But when multiple accents, a dozen cultures, scores of personalities, and multitude of preferences share bathrooms, toiletries, kitchens, sanctuaries, parking lots, and (I hesitate to even say it) sound systems, it can feel more like being caught in the middle of Armageddon (Rev 16:16-18). Ok, perhaps I exaggerate. But whenever groups of people who are striving to be unified in Christ are actually spending time in shared space for significant time, they must all sacrifice. I’ll even say they must feel like they are sacrificing beyond the others. This is necessarily the case because we cannot possibly see all the sacrifice of the other groups, but we are painfully aware of our own. And this is theologically required of us. This is slowly making our attitude Christ-like. Over time, as we love each other deeply, with effort and exhausting patience, we start to notice that our sisters and brothers are also laboring hard to put up with us. They don’t prefer our preferences any more than we prefer theirs. They don’t like learning that evidently there are more ways of putting away chairs or managing a nursery space than made sense to them any more than we do. But they have been trying hard (much harder than you realize) to “do nothing out of selfish ambition or vain conceit.” It turns out, it’s really hard to become more like Jesus, but theologically, it’s required. To follow Jesus, you have to actually, you know, follow. (Mark 8:34,35)