Jesus' primary concern—the very first petition of the prayer he teaches—is that more and more people, and more and more peoples, come to hallow God's name. This is the reason the universe exists. Missions exists because this hallowing does not.
— John Piper
Churches are not the kingdom of God, but are primary and inevitable expressions, outposts, and instrumentalities of presence of the kingdom among us. They are 'societies' of Jesus.