Midst
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)
Ezekiel 47:8-11
8
Then he said to me, These waters issue forth toward the eastern region, and shall go down into the Arabah; and they shall go toward the sea; into the sea [shall the waters go] which were made to issue forth; and the waters shall be healed.
9
It shall happen, that every living creature which swarms, in every place where the rivers come, shall live; and there shall be a very great multitude of fish; for these waters are come there, and [the waters of the sea] shall be healed, and everything shall live wherever the river comes.
10
It shall happen, that fishermen shall stand by it: from En Gedi even to En Eglaim shall be a place for the spreading of nets; their fish shall be after their kinds, as the fish of the great sea, exceeding many.
11
But the miry places of it, and its marshes, shall not be healed; they shall be given up to salt.
