Ephesians 4:1-16 reveals Paul's vision of the church. Check it out, it's fascinating.
Paul segues from unity (grounded in our one saviour) to diversity. For our world, perhaps the most important realisation is that the church can offer both unity and diversity in the one organism. Jesus doesn't make us all clones, rather he gives us different gifts and roles in the church so that we can build one another up into a strong body.
But there's something else fascinating in this passage, too: what it says about the goal of the church. This passage mentions nothing about social justice or transforming society or anything like that. Rather, "we are to grow up in every way into him who is the head, into Christ." (v. 15)
Certainly, when "each part is working properly," the "body [will] grow so that it builds itself up in love." (v. 16) The church is not a static organism, it is designed to grow. That is achieved by evangelism, sharing the good news of Jesus' death on the cross, which sets us free from sin and death.
But the church is not here on earth for some lesser purpose. If something is not communicating the gospel and drawing people closer to Christ it is not the church's work. We have limited human resources, and so we should make sure that they are directed such that "we all attain to the unity of the faith and of the knowledge of the Son of God." (v. 13)
Too often we worry that, unless we engage the surrounding culture in some way that catches their attention, we will not be able to share the good news. Yet Paul's vision of the church in Ephesians makes clear that if we focus on pressing closer to Christ, and equipping and encouraging one another in that endeavour, that will itself engage the surrounding culture.
The role of the church is to be the body of Christ on earth. Let us labour together to get that right and let God give the increase of souls each day. (Acts 2:47)