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)

6479. Some not so upright spirits who were once with me for quite a time were constantly introducing doubts that were based on the illusions of the senses and went against the idea that all things can flow in from a single source, and so from the Lord. But I told them that so many doubts could not be removed in a short space of time, on account of the illusions of the senses which had to be dispelled first and on account of their lack of knowledge of countless things which they needed to know first. Indeed I told them that with people who have a negative frame of mind, that is, who are ruled through and through by a negative attitude, doubts cannot by any means be removed; for with these people one small difficulty has more validity than a thousand proofs. With them one small difficulty is like a grain of sand placed right in front of the pupil of the eye, and although it is only a single grain and very tiny it nevertheless blocks one's entire field of vision. But people who have an affirmative frame of mind, that is, who are ruled through and through by an affirmative attitude, turn away small difficulties which are based on the illusions of the senses and go against truths; and any things they cannot grasp they cast aside, saying that they do not yet understand them, and in so doing hold fast to their belief in the truth. But the spirits mentioned above paid little attention to what they were told because of their negative frame of mind.