37. As for the statement that 'the lights will be for signs, and for set times, and for days, and for years', this contains more arcana than can be presented at this point, though no arcanum at all is visible in the sense of the letter. For now only this can be said: Change in spiritual and celestial things takes place both on general and on particular scales, and is comparable to changes that take place through the day and through the year. Changes through the day are from morning to midday, from then on to evening, and through the night to the morning. Changes in the year similar, from spring to summer, from then on to autumn, and through winter to spring. These bring changes in temperature and amount of daylight, and so in the fertility of the earth. Compared to such changes are the changes that take place in spiritual and celestial things. Life without changes and variations would lead to sameness, and so no life at all. Good and truth would not be recognized and identified, let alone perceived. In the Prophets such changes are called 'ordinances', as in Jeremiah,

[Thus] said Jehovah who gives the sun for light by day and the ordinances of the moon and of the stars for light by night, These ordinances will not depart from before Me. Jeremiah 31:35-36.

And in the same prophet,

Thus said Jehovah, If I have not established My covenant of day and night, the ordinances of heaven and earth . . . Jeremiah 33:25.

But these things will in the Lord's Divine mercy be dealt with at Genesis 8:12.

Water in the Bible represents true ideas about natural, external things – day-to-day life and physical existence. The sea represents the whole collection we have of these natural truths (to use a common term from the Writings). Those representations – like all other representations in the Bible – can be negative as well as positive; the water in the sea can also represent false thinking and twisted logic. This is especially true when a storm stirs up the sea and causes waves; the waves represent arguments which come from false and twisted thinking and which attack our belief in what's true. In most cases this comes in the form of temptation, when false thinking attempts to link up with our evil desires and convince us that it's OK – and even good – to go ahead and do what we want.

(റഫറൻസുകൾ: The Apocalypse Explained 419 [23-24], 538 [5])