Arcana Coelestia #434
434. Verse 25 And the man (homo) knew his wife again, and she bore a son, and she called his name Seth - for God has appointed me another seed in place of Abel, seeing that Cain had killed him.
'The man' and 'his wife' are here used to mean the new Church which earlier on was meant by 'Adah and Zillah'. 'Her son whose name she called Seth' means new faith, through which charity may be received 'God has appointed another seed in place of Abel, seeing that Cain had killed him' means that charity, which Cain separated and annihilated, was now conferred on this Church by the Lord.
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)