Can the church carry out a stronger mission? Can the church cause its message to be more convincing to an unbelieving world?
According to Jesus, the acknowledgement and completion of the unity of all believers is both mission and apologetics. It's what the church should do. And it's what causes the church to be credible.
I've heard preaching that emphasized that Jesus prayed for the unity of all believers, and that he uttered that prayer on the night he was betrayed, the timing adding to its significance.
What I haven't heard proclaimed as often are the purposes and results that Jesus connects to the unity of his people.
Jesus prayed that all believers would be in him and his Father "in order that the world may believe that you have sent me" (John 17:21).
Jesus prayed for believers that they would be brought to complete unity "to let the world know that you [the Father] sent me and have loved them even as you have loved me" (17:23).
Seems like important, powerful stuff, doesn't it? I like C. K. Barrett's comment on that phrase in verse 21:
"The unity of the church in God is the supreme testimony to the truth claim that Jesus is God's authorized emissary. The existence of such a community is a supernatural fact which can be explained only as the result of a supernatural cause. Moreover, it reveals the pattern of the divine activity which constitutes the Gospel: the Father sends the Son, and in his works the love of the Father for mankind is manifest, because the Son lives always in the unity of love with the Father; the Son sends the church, and in the mutual charity and humility which exist within the unity of the church the life of the Son and of the Father is reflected. The church's unity in word and faith means that the world is challenged to decide between faith and unbelief."
Some related questions I have are . . . .
1. Why isn't unity more of hot topic in the world of Christendom today?
2. Is it simply the case that we have gotten used to the concept of the church (universal) and the various churches making up that church?
3. Or is it more the case that the fragmented world of Christendom seems hopeless when it comes to unity?