878. And the sea was no more, signifies that the external of the heaven collected from among Christians, since the first establishment of the church, was in like manner dispersed, after they who were written in the Lord's book of life were taken thence and saved. By "the sea" is signified the external of heaven and of the church, in which are the simple, who have thought naturally and but little spiritually of things relating to the church; the heaven in which these are is called external (see n. 238, 239, 403, 404, 420, 466, 470, 659, 661); by "the sea" here is meant the external of heaven collected from among Christians from the first establishment of the church. But the internal heaven of Christians was not fully formed by the Lord, till a little before the Last Judgment, and also after it, as may appear from chapters 14 and 15, where it is treated of, and from chapter 20:4-5; see the explanations of which. The reason why this was not done before was because the dragon and his two beasts had dominion in the world of spirits and burned with the lust of seducing everyone they could, wherefore it was hazardous to collect them sooner into a heaven.
 The separation of the good from the dragonists, and the condemnation of the latter, and finally the casting of them into hell, are treated of in many places, and lastly in chapter 19:20, and in chapter 20:10; and after this it is said, that "the sea gave up the dead which were in it" (verse 13), by which are meant the external and natural men of the church called to judgment (see above, n. 869), and then the separating and saving of those who were written in the Lord's book of life, concerning which see the same article; this is "the sea" which is here meant. It is also said in another place, where the New Heaven of Christians is treated of, that it extended itself to "the sea of glass mingled with fire" (chapter 15:2); by which "sea" is also signified the external of the heaven of Christians (see the explanation, n. 659, 661). From these things it may appear that by "the sea was no more" is signified that the external of heaven collected from among Christians from the first establishment of the church, after they were taken thence and saved who were written in the Lord's book of life, was in like manner dispersed. Concerning the external of heaven collected from among Christians from the first establishment of the church, it has been granted me to know many particulars which it would be tedious to adduce in this place; save only that the former heavens, which passed away at the day of the Last Judgment, were permitted for the sake of those who were in that external heaven or sea, because they were conjoined by externals but not by internals, on which subject something may be seen above (n. 398). The reason why the heaven, where the men of the external church are, is called "the sea" is because their habitation in the spiritual world appears at a distance as if it were in the sea; for the celestial angels, who are angels of the highest heaven, dwell as it were in an ethereal atmosphere; the spiritual angels, who are angels of the middle heaven, dwell as it were in an aerial atmosphere; and the spiritual natural angels, who are angels of the lowest heaven, dwell as it were in a watery atmosphere, which, as was said, appears at a distance like the sea. Hence it is that the external of heaven is meant by "the sea" in many other places also in the Word.