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)

8985. 'And if the slave says plainly' means thought then springing from the implanted truth. This is clear from the meaning of 'saying' as thought, dealt with in 7094, 7107, 7244; and from the meaning of 'the slave' as truth without complementary good, dealt with in 8974, at this point this truth when it has been strengthened and implanted, since it is speaking of that slave when about to go out, 8984. 'The slave' is said to mean truth, though a person imbued with truth devoid of complementary good is meant. The reason for saying that 'the slave' means truth and not a person imbued with such truth is that when angels speak they do so in the abstract, that is, without envisaging actual persons. For in heaven they think about matters without envisaging persons, because when their thought involves persons it brings to mind a community associated with the matter they are thinking about; and when this happens their thought is narrowed down to and becomes fixed on that community.

[2] In heaven thinking about a place leads to being present in that place, and their presence in that community would attract towards itself the thoughts of those within the community, and so would disrupt the inflow from the Divine there. It is quite different when they speak in the abstract about some matter; their thought then spreads out in every direction in accord with the heavenly form which the influx emanating from the Divine produces, without causing disruption in any community. For it reaches into communities' general spheres, yet without having an effect on or unsettling anyone within the community, and so without impairing anyone's freedom to think in accord with the inflow from the Divine. In short, abstract thought can pass through the whole of heaven without hindrance anywhere; but thought narrowed down to persons or places becomes fixed and static.