In Deuteronomy 33:2, this means that the Lord made even the Natural in Himself Divine in order that this also might be a source of light, that is, of intelligence and wisdom. (Arcana Coelestia 4240)

4240. 'To the land of Seir' means celestial-natural good. This is clear from the meaning of 'the land of Seir' in the highest sense as the Lord's celestial-natural good. The reason why 'the land of Seir' has this meaning is that Mount Seir formed a boundary to the land of Canaan on one side, Joshua 11:16-17, and all boundaries such as rivers, mountains, and stretches of land represented the things that came last, 1585, 1866, 4116. Indeed these boundaries acquired their individual representations from the land of Canaan contained within them, which land represented the Lord's heavenly kingdom, and in the highest sense His Divine Human, see 1607, 3038, 3481, 3705. Things that are last, existing as boundaries, are those which are called natural, for natural things are the boundaries holding spiritual and celestial realities within them. This is so in the heavens, for the inmost or third heaven is celestial because it is governed by love to the Lord; the intermediate or second heaven is spiritual because it is governed by love towards the neighbour; and the last or first heaven is celestial-natural and spiritual-natural because it is governed by simple good, which is the last degree of order there. And the same is true with the regenerate person who is a miniature heaven. From all this one may now see the origin of the meaning of 'the land of Seir' as celestial-natural good. 'Esau' too, who dwelt there, represents that good, as has been shown above, and therefore the land where he dwelt has the same meaning. For lands take on the particular representations of their inhabitants, 1675.

[2] From all this one may now see what is meant in the Word by 'Seir', as in Moses,

Jehovah came from Sinai, and dawned from Seir upon them; He shone from Mount Paran, and came out of myriads of holiness. Deuteronomy 33:2-3.

In the Song of Deborah and Barak in the Book of Judges,

O Jehovah, when You went forth from Seir, when You set out from the field of Edom, the earth trembled, the heavens also dropped, the clouds indeed dropped water, the mountains flowed down, this Sinai before Jehovah God of Israel. Judges 5:4-5.

In Balaam's prophecy,

I see Him, but not now; I behold Him, but not near. A star will arise out of Jacob, and a sceptre will rise up out of Israel. And Edom will be an inheritance and Seir will be an inheritance of his enemies; and Israel is gaining strength. Numbers 24:17-18.

Anyone can see that in these places 'Seir' means some aspect of the Lord, since it is said that 'Jehovah dawned from Seir', that 'He went forth from Seir and set out from the field of Edom', and that 'Edom and Seir will be an inheritance'. But what aspect of the Lord is meant no one can know except from the internal sense of the Word. It is the Lord's Divine Human that is meant, and in particular the good of the Divine Natural within that Human, as may be seen from what has been mentioned above. 'Dawning from and going out of Seir' means that He made even the Natural Divine in order that this also might be a source of light, that is, of intelligence and wisdom, and in this way He might become Jehovah not only as regards the Human Rational but also as regards the Human Natural. This is why it is said that 'Jehovah dawned from Seir' and 'Jehovah went out of Seir' - the Lord being Jehovah, see 1343, 1736, 2004, 2005, 2018, 2025, 2156, 2329, 2921, 3023, 3035. Something similar is embodied in the prophetic utterance concerning Dumah,

One is calling to me from Seir, Watchman, what of the night? Watchman, what of the night? The watchman said, Morning comes, and also the night. Isaiah 21:11-12.

[3] In the relative sense 'the land of Seir' strictly speaking means the Lord's kingdom existing with those outside the Church, that is, with gentiles when the Church is being established among them, while the previous or old Church is simultaneously falling away from charity and faith. As is clear from many places in the Word, light comes at that time to those who are in darkness. And this is strictly speaking the meaning of 'dawning from Seir', and of 'going forth from Seir and setting out from the field of Edom'. It is also the meaning of 'Seir will be an inheritance', as well as of the words in Isaiah, 'One is calling to me from Seir, Watchman, what of the night? The watchman said, Morning comes, and also the night.' 'Morning comes' means the Lord's advent, 2405, 2780, and as a consequence enlightenment coming to people who are 'in the night', that is, who dwell in ignorance; but that enlightenment is from the Lord's Divine Natural, 4211. Since most things in the Word also have a contrary sense, so too does the name 'Seir', as in Ezekiel 25:8-9; 35:2-15, and in various places in the historical parts of the Word.