In the Bible, things that are lower down, or under, physically, generally represent things that are lower or more external spiritually. In some cases, the lower things have been separated and put away to protect the good, but in others, it can mean that a less exalted idea or good desire is supporting a more exalted one.

(References: Arcana Coelestia 4564 [1-2], 8610, 9656)

57. 'The plant yielding seed' is every truth that looks towards a use. 'The tree in which there is fruit' is the good that accompanies faith. 'Fruit' is what the Lord gives to the celestial man, while 'seed', the source of the fruit, is what He gives to the spiritual man. This is why it is said that 'the tree producing seed will be for you for food'. That celestial food is called 'fruit from a tree' is clear from the next chapter where the subject is the celestial man. Here let just that be mentioned which the Lord spoke through Ezekiel,

Beside the river there is rising up upon its bank, on this side and on that, every tree for food. Its leaf will not fall nor its fruit fail. It is re-born monthly, for its waters flow out from the Sanctuary, and its fruit will be for food, and its leaf for medicine. Ezekiel 47:12.

'Waters from the Sanctuary' means the life and mercy of the Lord, who is the Sanctuary; 'fruit' means wisdom, which is food for them; 'leaf' is intelligence, which is given them for a use, which is called 'medicine'. Spiritual food however is called 'a plant', as stated through David,

[Jehovah is] my Shepherd, I shall not want; He makes me ¹ lie down in green pastures. ² Psalms 23:1-2.

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