Augustine of Hippo

This city is said to come down out of heaven in the sense that God created it by means of heavenly grace, as he told it through Isaiah: "I am the Lord creating thee." Indeed, its descent from heaven began with the beginning of time, since it is by God's grace coming down from above through the "laver of regeneration" in the Holy Spirit sent from heaven that its citizenship has continuously grown up on earth. Yet only after God's last judgment, the one he has deputed to Jesus Christ his Son, will his tremendous gift of grace be revealed so brightly in [Jerusalem] that in this new brightness there will remain no traces of its earthly blemishes. For then its members' bodies will pass over from mortal corruptibility to the new immortality of incorruption.