896. 21:10 And he carried me away in the spirit onto a great and high mountain, and showed me the great city, the holy Jerusalem, descending out of heaven from God. This symbolizes John's being transported into the third heaven and his sight opened there, and the Lord's New Church in respect to its doctrine being presented to him in the form of a city.

John's being carried away in the spirit onto a great and high mountain means, symbolically, that he was transported into the third heaven, where those people dwell who are impelled by love from the Lord and possess a doctrine of genuine truth from Him. Greatness is also predicated of goodness, and height of truths.

His being carried away onto a mountain symbolically means into the third heaven, because he is said to have been in the spirit, and someone who is in the spirit is as to his mind and sight in the spiritual world. Moreover, in the spiritual world angels of the third heaven dwell on mountains, angels of the second heaven on hills, and angels of the lowest heaven in valleys between the hills and mountains. Consequently, when someone is carried away in the spirit onto a mountain, it symbolically means into the third heaven. This carrying away takes place in a moment, because it is achieved by a change in the person's state of mind.

The angel's showing to John symbolizes his sight being opened then and a revelation. The great city, the holy Jerusalem, coming down out of heaven from God symbolizes the Lord's New Church, as in nos. 879, 880 above, where we also explained why it is called a holy city, and why it is said to be coming down out of heaven from God. It was seen in the form of a city because a city symbolizes doctrine (nos. 194, 712), and a church is a church by virtue of its doctrine and its living in accordance with that doctrine. It was also seen as a city in order that its whole character might be described, and this is described by the city's walls, gates, foundations, and various dimensions.

The church is similarly described in Ezekiel, where we are also told that the prophet was taken in the visions of God onto a very high mountain, where he saw a city to the south, whose wall and gates an angel also measured, together with its various widths and heights (Ezekiel 40:2ff.).

The following passage in Zechariah has a similar meaning:

I said (to the angel), "Where are you going?" He said..., "To measure Jerusalem, to see how great its width is and how great its length." (Zechariah 2:2)