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.

8920. 'Speak yourself to us, [and we will hear]' means the reception of truth in an adjusted form, which - in that form - they will obey. This is clear from the meaning of 'speaking' as influx and communication, dealt with in 2951, 3060, 4131, 5481, 5797, 6225, 7270, 8128, and therefore also as reception since what flows in and is communicated is received; and from the representation of Moses, the one who should speak, as the truth from God below heaven joined to God's truth in heaven, thus the intermediary between the Lord and the people, dealt with in 8760, 8787, 8805. So it is that here 'Moses' is truth in an adjusted form.

[2] As regards truth in an adjusted form, it should be recognized that when God's truth comes down by way of the heavens to people in the world, as the Word came down, it undergoes adjustment for all on its way down, both for those in heaven and for those on earth. But the form in which God's truth exists in the heavens is completely different from that in which it exists in the world. In the heavens that truth is as it exists in the internal sense of the Word, in the world it is as it appears in the literal sense. Indeed in the heavens themselves it exists in diverse forms - in one form in the inmost or third heaven, in another in the middle or second heaven, and in yet another in the first or lowest heaven. The form that God's truth takes - that is, the perception, thought, and utterance of it - in the inmost or third heaven is so superior to the form it takes in the middle or second heaven that it is not comprehensible there; it is so Divine and matchless. It contains countless things which cannot find utterance in the second heaven; it consists of nothing other than the changes of state which the affections inherent in love undergo. Yet the form God's truth takes in the middle or second heaven is in like manner superior to the one it takes in the first or lowest heaven, and is even more superior to the form God's truth takes in the world. So it is that the things which find utterance in those heavens are of a kind that no human mind has ever perceived or any ear has heard, as those who have been raised to heaven know from experience.

[3] People who have no knowledge of this suppose that those in the heavens think in the same way and speak in the same way as on earth. But they suppose this because they do not know that the interior aspects of a person belong to a higher level of existence than exterior ones do, or that the thought and speech of those in the heavens is celestial and spiritual, whereas on earth it is natural, the difference between the two being so great that words cannot describe it. But regarding those types of speech, see 1634-1650, 1757-1759, 1876, 2157, 2472, 2476, 3342-3345, 4104, 4609, 5225, 5287, 6040, 6982, 7002, 7089, 7131, 7191, 7381, 8343, 8733, 8734.

[4] From all this also it is evident that unless God's truth or the Word appeared in an adjusted form it would be unintelligible. For if it were above people's level of perception it would not pass into understanding or accordingly into faith. This is why God's truth has been given to mankind in the form taken by the Word in the letter; for if it were to appear in the form in which it exists in heaven, it would be unintelligible to anyone in the world. As soon as anyone glanced at it and saw what was in it, it would be cast aside, since it would not consist in images such as belong to natural light. Furthermore it would be full of arcana which could not possibly find a place in a person's way of thinking because they would be entirely at odds with the appearances and illusions derived from the world through the outward senses - not to mention the copious chain of deeper arcana which lie hidden within those arcana and cannot be expressed except by variations and changes in the state of heavenly light and flame, by means of which angelic speech and thought are carried on.