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)

300. Sealed up with seven seals, signifies altogether hidden, namely, the state of life of all in heaven and on the earth. This is evident from the signification of "sealed with seals," as being to be hidden, for what is contained in a book sealed up with seals no one knows until it is opened and read; also from the signification of "seven," as being all persons and all things, also what is full and entire (See above, n. 257); thus also altogether, because this means fully and wholly.