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 #3772
3772. 'And water the flock' means that the doctrine was drawn from it. This is clear from the meaning of 'watering', or giving a drink, as giving instruction, dealt with in 3069, 3768, and from the meaning of 'the flock' as people who are governed by the goods and truths of faith, dealt with in 343, 3767. Thus 'watering it' means giving instruction from the Word, and therefore from doctrine.