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)

793. From this point onwards to the end of the present chapter the subject is the people before the Flood who perished. This becomes clear from the details in the description given. People who possess the internal sense can recognize instantly, and indeed from any single word, what the subject is, better still from the combination of many. When the subject changes different words instantly appear, or else the same words combined differently. The reason is that some words are peculiar to spiritual matters, others peculiar to celestial; or what amounts to the same, some are peculiar to things of the understanding, others to those of the will. For example, 'desolation' is a word used of spiritual things, 'vastation' of celestial; 'city' is used of spiritual, 'mountain' of celestial; and so on. The same applies to combinations of words. And what is bound to amaze everybody, the difference in Hebrew is frequently just a matter of vocalization. In what belongs to the class of spiritual words the first three vowels [of the alphabet] are normally prominent, but in the case of what is celestial the last two. The fact that these verses contain a different subject is also discernible from the repetition discussed already. That is to say, the statement, 'And the waters grew stronger and stronger over the earth', is a repetition of what has already been stated in the previous verse. It is also discernible from everything that follows.