Two thousand years ago, Jesus didn't give his followers the Church, he gave them a mission: "Be my witnesses in Jerusalem, all of Judea and Samaria, and to the ends of the Earth." (Acts 1:8) 

In the books of Acts, we see that the Church ends up being a natural product of a group of people living out that mission together. The problem is when we lose sight of the mission, we end up losing the Church. And we cease to be good news to the world around us.