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.

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

22. Verse 5 And there was evening, and there was morning, the first day.

What 'evening' means, and what 'morning', is recognized from what is said above. 'Evening' means every prior state, because it is a state of shade, that is, of falsity and of absence of faith, while 'morning' is every subsequent state, because it is one of light, that is, of truth and of cognitions of faith. 'Evening' in general means all the things that are man's own, whereas 'morning' means all those that are the Lord's, as is said through David,

The Spirit of Jehovah has spoken within me, and His word is upon my tongue. The God of Israel has said, the Rock of Israel has spoken to me. He is like the morning light, when the sun is rising on a cloudless morning, shining bright, as when after rain tender grass [springs up] from the earth. 2 Samuel 23:4.

Because 'evening' is a time when there is no faith, and 'morning' when there is, the Lord's Coming into the world is called 'the morning', and the time at which He comes, since faith does not exist at that point, is called 'the evening', as in Daniel,

The Holy One said to me, Up to the evening when it is becoming morning, two thousand three hundred times. Daniel 8:13-14.

In the Word, 'morning' stands in a similar way for every coming of the Lord, and so is a term describing the new creation.