The "midst" of something in the Bible represents the thing that is most central and most important to the spiritual state being described, the motivation that drives everything else. In general this will be something we love or feel, because at the core of things we are what we love; our loves define us.

(Notae: Apocalypse Revealed 44, 90, 268; Arcana Coelestia 2252, 2940, 10153, 10365, 10557, 10635, 10641)

90. "'Which is in the midst of the Paradise of God.'" This symbolically means, inwardly in the truths of wisdom and faith.

In the midst means, symbolically, the inmost (nos. 44, 383), here within or inwardly. The Paradise of God symbolizes truths of wisdom and faith. Consequently the tree of life which is in the midst of the Paradise of God symbolizes the Lord accompanied by the goodness of love and charity inwardly in the truths of wisdom and faith. Good also exists inwardly within truths, for good is the essence of life, and truth is the consequent expression of life, as we showed many times in Angelic Wisdom Regarding Divine Love and Wisdom.

That the Paradise of God is the truth of wisdom and faith is apparent from the symbolic meaning of a garden in the Word. A garden there symbolizes wisdom and intelligence, because trees symbolize the people of the church, and their fruits goods of life. That is what the Garden of Eden symbolizes, for it describes the wisdom of Adam.

[2] The garden of God in Ezekiel has the same meaning:

With your wisdom and your understanding you have gained riches for yourself... You were in Eden, the garden of God; every precious stone was your covering... (Ezekiel 28:4, 13)

The subject is Tyre, which symbolizes the church in respect to its concepts of truth and good, thus in respect to its intelligence. Accordingly it is said, "With your wisdom and your understanding you have gained riches for yourself." The precious stones which served as its covering symbolize truths of intelligence.

[3] In the same book:

Assyria was a cedar in Lebanon... The cedars in the garden of God did not hide it... No tree in the garden of God was like it in beauty... All the trees of Eden envied it... in the garden of God. (Ezekiel 31:3, 8-9)

This is said of Egypt and Assyria, because Egypt symbolizes knowledge, and Assyria rationality, which leads to intelligence. A cedar has a similar symbolism.

But because Egypt's rationality led also to a conceit in its own intelligence, therefore it is said of it,

To which of the trees in Eden were you then likened in glory and greatness, when you were brought down with the trees of Eden to the earth below, and you lay in the midst of the uncircumcised...? (Ezekiel 31:18)

The uncircumcised are people who lack the goodness of charity.

[4] In Isaiah:

...Jehovah will comfort Zion..., and make her wilderness like Eden, and her desert like the garden of Jehovah. (Isaiah 51:3)

Zion there is the church. The wilderness and desert are a deficiency of truth and ignorance of it. Eden and the garden of God are wisdom and intelligence.

Wisdom and intelligence are also symbolically meant by a garden in Isaiah 58:11; 61:11, Jeremiah 31:12, Amos 9:14, and Numbers 24:6.

[5] A person of the church is also like a garden in respect to his intelligence when he possesses goodness of love from the Lord, because the spiritual warmth that enlivens him is love, and spiritual light is the resulting intelligence.

People know that these two, warmth and light, cause gardens in the world to bloom. It is the same in heaven. Paradisal gardens are seen in heaven, with trees bearing fruit in accordance with the inhabitants' wisdom that springs from their goodness of love from the Lord. But around people who possess intelligence without the goodness of love, no gardens are seen, but grass, while around those whose faith is divorced from charity, not even grass is seen, but sand.