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)

2875. Goodness of life, or the affection for good, is instilled by the Lord by means of an internal way, without the person being at all aware of it, whereas the truth of doctrine, or faith, is instilled by an external way and introduced into the memory. From there it is called forth by the Lord in His own time and according to His own order and is joined to the affection for good. This happens in that person's freedom, for a person's freedom, as has been stated, flows from his affection. This is how faith is implanted and takes root. Whatever is done in freedom is joined to him, but that which is done under compulsion is not. This may become clear from the fact that nothing can possibly be joined to a person unless he has an affection for it. Affection is that which actually receives, and anything received that is contrary to his affection is contrary to his life. From this it is evident that the truth of doctrine, or faith, is incapable of being received except by the affection for it. But as is the affection so is the reception. It is the affection for truth and good, this alone, that receives the truth of faith, for they accord with each other, and because they accord they join themselves together.