<p>21:18 <i>And the building of the wall was of jasper</i>- Why a wall? It can hardly be for protection. Perhaps there will eternally be a sense of separation between light and darkness, saved and unsaved, which we do well to be aware of now too.</p><p><i>And the city was pure gold, like pure glass</i>- See on :21 <i>pure gold</i>. Glass was not totally transparent in John's day, but he saw glass as if it were transparent, and had the impression this was in fact transparent gold (:21). Yet gold by its nature cannot be transparent. In these paradoxes we have reflected the wonder of the whole thing. The city of God, the Kingdom of God, is transparent- it is <i>open</i>. The gold, the wonderful reality which by its nature is closed and dense, is also amazingly open and transparent. For a theme of these visions is that the unbelieving world those not destroyed during the last judgments are invited to come in to the Kingdom, to the community of believers, the Jerusalem which is above which has now been revealed on earth. The gates are open day and night, the wall is there- but transparent; the city itself is the ultimate image of openness. The bride and the Lord Jesus are urging the nations to come into it. No longer do the 12 tribes of Israel define membership- the symbolism of 12 x 12 gives the impression of an innumerably greater openness. The spirit of that openness is to be seen in us today.</p>