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.

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

6191. Experience enabling me to know that the Lord governs a person by means of angels and spirits has been so conclusive that I have been left with not the slightest shadow of doubt. For many years now all my thoughts and all my affections, down to the last detail, have flowed in by means of spirits and angels. This I have been allowed to perceive so plainly that nothing could be plainer; for I have perceived, seen, and heard who exactly the spirits or angels were, what they were like, and where they came from. And whenever anything inimical has come into my thought or will I have spoken to and rebuked those who were responsible. I have also noticed that their power to introduce any such thing was curbed by the angels, observed how this was done, and also seen that they were often driven away by the angels. When they had been driven away, I noticed that in their place new spirits were present, from whom influx again took place. I was also allowed to discern where those spirits were from, that is, of which communities they were emissaries.

[2] Besides this I have often been given the opportunity to talk to those actual communities. Although every one of my thoughts and affections, down to the last detail, was flowing in through spirits or angels, my thinking was nevertheless as it had been before, and my desires as they had been before. I mixed with other people as I had done before, without anyone noticing any difference in my life from what it had been before. I realize that scarcely anyone will believe what I am saying; but all the same it is the absolute truth.