"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." [The Apostle Paul, in Philippians 2:1-4]
In John 17, Jesus prays that his followers would be, above all, united together as Jesus is united with the Father. The early church had a word for this likeness: homoousios, meaning of the same substance.
I dare you to try and fit that one into conversation today.
God the Father and Jesus are of the same stuff; if you see one, you see the other. But as you read through the Bible, sometimes it seems that on the surface, God the Father (especially in the Old Testament) and God the Son (Jesus, in the New Testament) aren't really that related; one burns Sodom and Gamorah, the other heals beggars and lepers. But if you look more closely, you start to see that God the Father really is generous, loving, and actually likes his creation, and that Jesus sometimes gets upset and turns over tables. The more you read, the more you see that they are united in the same stuff - the stuff of character - and it is most profound to note that God the Father and God the Son are servants. God begins the restoration of His world by rescuing Israel from slavery, something none of the other religions of the day could claim. Jesus, over and over again, heals people physically, emotionally, socially, and spiritually in nearly every place He went. It makes me think that unity in our body, as diverse as we are, as seemingly different as we are in our theology, in our expression, in our worship, means that we need to all be of the same character, of the same stuff.
We need to be united because we take on the character of God, and the best way to do that is to love each other. And the best way to love each other is not at first a head thing, and not even at first a heart thing, but is at first an action thing: to serve. Serving is at the very core of God's character, and is, I think, at the very heart of what it means to be a united body, in the name - in the character - of Jesus.
I've never seen people who serve together angry at one another for very long. When we SERVE others WITH others, we can put our differences aside because it's no longer about us, it's about the mission and the One who gave us that mission, it's about the purpose we've adopted that's outside of ourselves. When we need to, we can still work with others we don't agree with or don't even like much because we're all in on the mission together. And when our self-attention goes out the window and we instead gravitate that attention to the mission, so too does our focus on the differences we see between ourselves and others seem to dissipate. Unity is about our focus; when we are not united it is because we are too focused on loving ourselves instead of on loving others. Disunity, at its heart, is about selfishness.
The heart of unity is selflessness and humility, just like serving.
"The eleven disciples went to Galilee, to the mountain where Jesus had told them to go. When they saw him, they worshiped him; but some doubted. Then Jesus came to them and said, 'All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.'" [Jesus, in Matthew 28:16-20]