On the night before he died, as he instituted the Eucharist, Jesus prayed for the unity of his disciples when he said,
“I pray not only for them, but also for those who will believe in me through their word, so that they may all be one, as you, Father, are in me and I in you, that they also may be in us, that the world may believe that you sent me.”
– Jn 17:22-21.
Jesus prayed for a unity in the Church. We must take this prayer very seriously. For if we do not take seriously the Son who suffered and died for us, then we do not take seriously the Father who raised Him up in the Spirit. The credibility of the gospel depends on a unified witness.
Well, quite frankly, we blew it. Over the last 20 centuries, the Church as seen several major divisions occur. The first was the breaking off of the Coptic Churches in the fourth century, then the Great Schism of the 11th century between the Catholic West and the Orthodox East, and then the one that most of us are familiar with, the Reformation in the 16th century which saw the establishment of the Protestant communions.
As long as Christians could live in relative isolation, the effects of a divided Church seemed tolerable. But as the years went by and Christian missionaries of all denominations continued their work in the world, they were continually frustrated by the effects of such division. Indeed, they found that the biggest stumbling block to the spread of the gospel is a divided Christianity.
“Ecumenism” is the term typically used to refer to the modern ecumenical movement which works, little by little, to repair the sad divisions in Christianity so that we may indeed “be one…so that the world may believe.”
The operative principle is that of “convergence.” The idea is that we all meet in Christ. Think of a wagon wheel with Christ at the hub and all the rest of us on the spokes. As we get closer to Christ, we get closer to one another.
The divisions in the Church did not occur overnight and so the process to repair them will take some time, perhaps decades or centuries.