Apocalypse Explained#241
241. Verse 18. I counsel thee, signifies the means of reformation of those who are in the doctrine of faith alone. This is evident from what now follows, for the reformation of those who are in that doctrine is now treated of; therefore "I counsel thee" implies precepts as to how such must live that they may be reformed and thus saved.
Arcana Coelestia#8138
8138. 'In Pharaoh and in all his army' means the submersion into hell of those steeped in falsities arising from evil, and their encompassment there by falsities as if by waters. This is clear from what has been mentioned immediately above in 8137, that 'Pharaoh' means those who were cast into hell, as also does 'his army', 'Pharaoh' being those steeped in falsities arising from evil, and 'his army' the falsities themselves. 'Armies' are truths springing from good, see 3448, 7236, 7988, and therefore in the contrary sense they are falsities arising from evil, 3448. The expression 'encompassment by falsities as if by waters' is used because falsities that arise from evil - the kind of falsities that exist with those belonging to the Church who have championed separated faith and have led a life of evil - are seen there as waters, 8137. This also is why deluges of water mean situations in which truth is laid waste while the water present in them means falsities, 705, 739, 756, 6346, 6853.