Seven, as in Revelation 15:1, signifies everything in an universal sense. The number 'seven' was considered holy, as is well known, because of the six days of creation, and the seventh, which is the celestial self, where peace, rest, and the Sabbath is. The number seven occurs so frequently in the rites of the Jewish church and is held holy everywhere.

So times were divided into seven, longer and shorter intervals, and were called weeks, like the great intervals of times till the coming of the Messiah, in Daniel 9:24-25. The time of seven years is called 'a week' by Laban and Jacob, as in Genesis 29:27-28. So wherever the number seven occurs, it is considered holy and sacred, as in Psalm 119:164, and in Isaiah 30:26.

As the periods of a person's regeneration are distinguished into six, prior to the seventh, or the celestial self, so the times of vastation are also distinguished, until nothing celestial is left. This was represented by the many captivities of the Jews, and by the last Babylonian captivity, which lasted seven decades, or seventy years. This was also represented by Nebuchadnezzar, in Daniel 4:16, 22, 29. It also refers to the vastation of the end times, in Revelation 15:1, 7-8. They should 'tread the holy city under foot, forty and two months, or six times seven,' as in Revelation 11:2 and Revelation 5:1. So the severity and increments of punishment were expressed by the number seven, as in Leviticus 26:18, 21, 24, 28 and Psalm 79:12.

(Odkazy: Apocalypse Explained 5, 7-8, 15; Arcana Coelestia 395; Daniel 9, 9:24, 9:25; Psalms 119)

7. Things which must quickly come to pass, signifies which will certainly be. This is evident from the signification of "things which must come to pass," as being things that must needs be; and from the signification of "quickly," as meaning what is certain and full (Arcana Coelestia 5284, 6783). Those who look at all things in the Word according to the sense of the letter do not know otherwise than that "quickly" signifies quickly; thus here, that the things predicted in Revelation were to occur quickly; from which they are led to wonder that nevertheless so long a time has elapsed before the Last Judgment took place. But those who know the internal sense of the Word, do not understand "quickly," but certainly.

They see that "quickly" means certainly, because quickly involves time, and time is proper to nature; thus quickly is a natural, not a spiritual expression; and in the Word, all natural expressions signify the spiritual things that correspond to them; for the Word in its bosom is spiritual, while in the letter it is natural. Thence it is that "quickly" signifies what is certain. (That time is proper to nature, and, in the spiritual world, corresponds to state of life, may be seen in the work on Heaven and Hell, in the chapter on Time in Heaven, n. 162-169.)