Unity is not an option.
Jesus Christ demands that His church be united. He provides no loopholes or exceptions. We are to be one.
In John chapter 17 we find Christ's famous High Priestly Prayer. One of the primary themes of that prayer is Jesus' expectation that His body will be united. In this incredible prayer we read:
I do not ask for these only, but also for those who will believe in me through their word, that they may all be one, just as you, Father, are in me, and I in you, that they also may be in us, so that the world may believe that you have sent me. The glory that you have given me I have given to them, that they may be one even as we are one, I in them and you in me, that they may become perfectly one, so that the world may know that you sent me and loved them even as you loved me (John 17:20-23).
Jesus prays that we will be one as the Father and Son are one. In other words, our Lord expects perfect unity. Jesus goes on to tie the effectiveness of gospel proclamation to the unity of the body. These are some extremely significant words by Christ.
Not long after Jesus' death, resurrection, and ascension we read of the early church in the book of Acts. Luke paints a beautiful picture of unity for us:
And they devoted themselves to the apostles' teaching and the fellowship, to the breaking of bread and the prayers. And awe came upon every soul, and many wonders and signs were being done through the apostles. And all who believed were together and had all things in common. And they were selling their possessions and belongings and distributing the proceeds to all, as any had need. And day by day, attending the temple together and breaking bread in their homes, they received their food with glad and generous hearts, praising God and having favor with all the people. And the Lord added to their number day by day those who were being saved (Acts 2:42-47).
We know, however, that all was not hunky-dory in the world of the early church. As the gospel spread and churches were planted some of the early believers struggled with unity. Paul in particular wrote to these assemblies to instruct them in the importance of being one. Paul offers no exceptions to the command for unity. Below are three examples:
I appeal to you, brothers, by the name of our Lord Jesus Christ, that all of you agree, and that there be no divisions among you, but that you be united in the same mind and the same judgment (I Cor. 1:10).
I therefore, a prisoner for the Lord, urge you to walk in a manner worthy of the calling to which you have been called, with all humility and gentleness, with patience, bearing with one another in love, eager to maintain the unity of the Spirit in the bond of peace (Eph. 4:1-3).
So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy, complete my joy by being of the same mind, having the same love, being in full accord and of one mind (Phil. 2:1-2).
Christ's church today is splintered into thousands of different factions. These have another name: denominations. Within these denominations, local churches often have statements of faith and membership roles that separate those who are in from those who are out. Some even deny the Lord's Supper to Christians who haven't joined their particular church. All of this flies in the face of Christ's command for unity.
Christian unity has no justifiable exceptions. All dividing walls beyond the gospel need to be removed. Christ wants His body to be one; we must do all we can to make this a reality. How do we do we accomplish it? Paul tells us in Philippians chapter 2. The key to unity is humility. Immediately after Paul calls the Philippian believers to unity he writes in 2:3-4, "Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves. Let each of you look not only to his own interests, but also to the interests of others."
Unity is a wonderful thing. It brings great joy within the body. More importantly, Christ commands and demands it. We make this happen through the simple yet profound act of treating others better than ourselves.