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)

2888. The truth of the matter is that the life which anyone has, whether man or spirit, or angel also, flows in solely from the Lord, who is Life itself, and spreads itself throughout the whole of heaven, and of hell also, and in this way enters into each individual, doing so according to an order and sequence beyond comprehension. But this inflowing life is received by each according to his own disposition. Good and truth are received by those who are good as good and truth, but by those who are evil as evil and falsity, and are also converted among such into evil and falsity. It is like the light of the sun which spreads itself into all objects on earth but is received according to the specific nature of each object, possessing a beautiful colouring in forms that are beautiful, and a hideous colouring in forms that are hideous. In the world this is an arcanum, but in the next life nothing is known better. To enable me to know the nature of such influx I have been allowed to speak to the spirits and to the angels present with me, and also to feel and perceive their influx, which has happened more times than I can number. But I realize that people will still be misled into believing that what they will is from themselves, and that what they think is from themselves, thus that they have life from themselves. But nothing could be further from the truth.