The harmony that John sees symbolized in the square shape of the city is intended to characterize the Bride of Jesus Christ in her perfection. The church today has the privilege to preach this harmony between redeemed sinners and their Saviour, as well as the privileged obligation to enact this harmony in the Christian's relation with the other. A church that does not forgive a repentant sinner or enact that forgiveness in an active communion of saints is not a church of Jesus Christ. See Acts 2:41–47 and Acts 4:32–37 for examples of the harmony and care redeemed sinners show one another.
When the church is completed on the Last Day, every inhabitant will experience perfect safety. Members of the church of Jesus Christ today need to experience something of that safety today already. In a world where people hurt people, the church is meant to be a safe place for the vulnerable.
16 The city lies foursquare, its length the same as its width. And he measured the city with his rod, 12,000 stadia. Its length and width and height are equal.