20“I ask not only on behalf of these, but also on behalf of those who will believe in me through their word,21that they may all be one. As you, Father, are in me and I am in you, may they also be in us, so that the world may believe that you have sent me. 22The glory that you have given me I have given them, so that they may be one, as we are one, 23I in them and you in me, that they may become completely one, so that the world may know that you have sent me and have loved them even as you have loved me. 24Father, I desire that those also, whom you have given me, may be with me where I am, to see my glory, which you have given me because you loved me before the foundation of the world.
25“Righteous Father, the world does not know you, but I know you; and these know that you have sent me.26I made your name known to them, and I will make it known, so that the love with which you have loved me may be in them, and I in them.”
"Unity" is such a misunderstood Christian notion. Unity among different denominations. Unity among different Christian movements. Unity among different leaders. And so on.
If the history of the Christian Church tells us anything, it's been a history, not of unity, but its very opposite: disunity and fragmentation. The schism between the East and West, the split between the Catholics and Protestants, the splintering among various types of Protestants. In some sad cases, Christians were spending so much time fighting each other that the devil had very little work to do since these folks were doing such a good job bickering, accusing, and hating each other. The devil should have collected unemployment benefits.
But not all disunity or unity is the same. In fact, some disunity is worthwhile, if the disuniting is based on fundamental differences about hugely important matters, like the person and work of Jesus, the authority of Scripture, whether God is Triune, and other issues that determine the essence of Christianity.
More to the point for our purposes however, what type of unity is Jesus praying about in the passage above?
It's not doctrinal unity, nor denominational, nor any other type of unity listed above. It's the unity that Jesus himself has with the Father! Jesus prays that that type of unity -- what past theologians have called mysterium communio, or perichoresis -- would exist among believers. We cannot get to the same in-depth, interpenetrating unity that the Son has with the Father (and the Spirit), but nonetheless, this type of unity is what we are shooting for.
In simpler terms, Jesus is talking about unity of deep love for one another, such as that we have one another in our hearts. Think of your children (for those who have kids). Even when you are at work and they are at school, you have them "in your heart." The unity of hearts and deep affection is what Jesus has in mind, if I may be so bold to say. Whatever intimacy we can have with one another, that is unity. Loving each other for the other's sake. This unity becomes the basis of our witness to the world and this unity becomes also the source of healing and hope for those who enter into a community of faith and this unity becomes the source of strength even for spiritual warfare. People who love well and are loved well are better advancers of God's Kingdom.
Let's pray: O Lord, pour out your love into our hearts that we might be better lovers of one another. Grant us the power to forgive and be generous. Grant us your eyes of mercy and compassion. And grant us the affectionate, prayerful hearts for one another that'll embrace all those around us for who they are. In Jesus name, Amen.