Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
The following commentary covers Chapters 47 and 48.
The last two chapters do not require any lengthened remarks. The waters that issue from the sanctuary represent the life-giving power that proceeds from the throne of God, flowing through His temple, and healing the Dead Sea, the abiding token of judgment. The waters abound in fish, the trees that grow beside them are filled with fruit, the marshes alone remain under the curse-they are "given to salt." The blessing of that day is real and abundant, but not complete. The land is divided between the tribes in a new manner, by straight lines drawn from east to west. The portion for the sanctuary and for the city, or the 25,000 square reeds, are situated next to the seventh tribe, beginning from the north. The name of the city thenceforth shall be "Jehovah is there." Compare, for the waters that flow from the temple, Joe 3:18; Zac 14:8 - passages that refer to the same period.
It appears that the two places pointed out to the fishermen as a boundary were the two extremities of the Dead Sea (we may compare Gen 14:7; Ch2 20:2; and Isa 15:8). The main features in the whole passage are the re-establishment of Israel, but on new grounds and blessing, analogous to that of paradise (an image borrowed from this prophecy in the Apocalypse) [See Note #1]; but, after all, with the reserve that this blessing did not absolutely remove all evil, as will be the case in the eternal ages.
There is a powerful and abiding source of blessing which greatly surmounts the evil, and almost effaces it; nevertheless it is not entirely taken away. Still the name of the city, of the seat of power, that which characterises it, is "Jehovah is there"-Jehovah, that great King, the Creator of all things, and the Head of His people Israel.
Note #1
When I say "borrowed," it is not that the Spirit of God has not given us an original image in the Apocalypse: one has but to read it to be convinced of the contrary. But Old Testament imagery is constantly employed in the descriptions there given-only in such a manner as to apply it to heavenly things, a circumstance that makes it much easier to understand the book by helping us to enter into its real character through its analogy with the Old Testament.