When 'islands' are contrasted to 'earth' or 'mountains,' they signify the truths of faith, because they are in the sea. They signify doctrinal things which are rituals. 'Islands' signify peoples who are more remote from the worship of God. People who are steeped in the internal sense of the Word, such as angels, do not know what islands are, because they no longer have any concept of such places. Instead they have a perception of more remote worship, like the gentiles outside the church.

'Islands,' in Ezekiel 27:6, signify people in the church in a natural, materially-oriented state but still rational.

(Izinkomba: Apocalypse Explained 406; Isaiah 1, Isaiah 49, 49:1)

659. 15:2 And I saw as though a sea of glass mingled with fire. This symbolizes the farthest boundary of the spiritual world, where those people were gathered who had religion and consequently worshiped, but lacked any goodness of life.

The sea of glass in chapter 4:6 symbolized a new heaven formed of Christians who possessed general truths taken from the literal sense of the Word (no. 238). Those who possess general truths are also at the boundaries of heaven, and from a distance they appear, therefore, as though in the sea (nos. 398, 403, 404, 470). Here, however, the sea of glass symbolizes the farthest boundary of the spiritual world, where those people were gathered who had religion and consequently worshiped, but lacked any goodness of life. Because the gathering of these is symbolically meant, therefore the verse says as though a sea of glass, and the sea also appeared to be mingled with fire - the fire there symbolizing a love of evil and the accompanying evilness of life (nos. 452, 468, 494, 766, 767, 787), thus no goodness of life. For where good is absent, there evil is present.

That the gathering of these people is meant by the description, as though a sea mingled with fire, is apparent also from the depiction that follows next, that standing beside the sea of glass were those who had the victory over the beast and over his image. These symbolize people who, because of their rejection of a faith divorced from charity, had led a good life and were therefore in heaven (no. 660).

This sea is also the one meant in chapter 21:1, the sea which was no more (no. 878).

What this sea was like, and the character of the people there, is something I was also given to see. They were people who had religion, went regularly to church, listened to sermons, and partook of the Holy Supper, but beyond this gave no thought to God, salvation or eternal life, not knowing what sin is. Consequently they were human in visage, and most of them human also as regards their civic and moral life, but not at all as regards any spiritual life, which is the life that nevertheless makes a person human.