Is Christ divided? Paul asks the question in 1 Corinthians 1. How ludicrous. Christ is not divisible. And as born-again believers, our common identification with Christ, our unity with Christ, makes us "one" with every other true Christian.
So when we live with anger, bitterness and unforgiveness toward one another, we are not only sinning against each other; we are also sinning against Christ. Our visible unity and love for each other is the final apologetic that broadcasts to a watching world that Jesus Christ IS the true Son of God, because how else can anyone explain such loving unity amidst diversity? (see John 17) At the same time, our visible disunity and lack of love for each other broadcasts the opposite message: that Christians are no different from Muslims or Buddhists or Atheists. Our disunity causes unbelievers to stumble into justifying their continued disbelief. People go to hell partly because those on their way to heaven don't act like real Christians.
In Acts 9, on the road to Damascus, Christ asked Saul, "Why are you persecuting Me?" Whenever we hurt someone who is part of Christ's Body, or rail on someone who has been redeemed by His blood, we are hurting Christ Himself.
All our bragging about "who's right" stops at the cross. All of our over-confidence about the correctness of my viewpoint and the moral superiority of my choices, all the side-choosing and sloganeering of "I am of Paul, or Apollos", of "I am wiser, or more virtuous, or more connected", all falls dead at the foot of the cross (1 Cor. 1:26).
What things really matter when determining "with whom can I have fellowship?" Moral purity matters. Theological truth matters. Embracing diversity (as opposed to uniformity) matters. These are things Christians must talk about with each other, face to face, with each one surrendered to the authority of the Bible under the Lordship of Christ. These are legitimate issues to debate and discuss (without fear of disrupting an artificial, superficial "peace"). But most of the issues that divide us are not things that really matter. Most of the divisions about preferences are unnecessary and futile, a waste of time. Paul says in 2 Timothy 2:23 - "Don't have anything to do with foolish and stupid arguments, because you know they produce quarrels."
The path from disunity to unity is strewn with land mines and heartache. Taking that path requires that we die to ourselves. But that's OK. My Lord says that's part of His agenda for transforming us to become more like Him.
Blessed are the peacemakers, for they shall be called the children of God (Matthew 5).
