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.

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

43. Verse 22 And God blessed them, saying, Be fruitful and multiply, and fill the waters in the seas; and let birds be multiplied upon the earth.

Everything that has life in it from the Lord is fruitful and multiplies without limit. This does not happen during a person's lifetime, but in the next life it does so to an astonishing extent. In the Word 'to be fruitful' has reference to matters of love, while 'to multiply' has reference to matters of faith. The fruit of love contains the seed by which it multiplies itself to so great an extent. The Lord' s blessing also means, in the Word, fruitfulness and multiplication, for they are the outcome of that blessing.

Verse 23 And there was evening, and there was morning, a fifth day.