Rivers and streams of water; rather, rivulets, courses of water. Channels, along which water was conveyed for the purpose of irrigation, are intended (comp. Ezekiel 47:1-12; Joel 3:18). No doubt there is a secondary allegorical meaning running through the whole description of Judah's prosperity (Isaiah 30:23-26).
In this allegorical intention the waters stand for the streams of God's grace. In the day of the great slaughter. Equivalent to "the day of vengeance" (Isaiah 34:8) the day when God shall tread down his enemies.
The prophet passes from the immediate effect of Judah's repentance to a broader view of what shall happen when God's kingdom is established upon the earth. When the towers fall; i.e. when there shall be a general "pulling down of strong holds," and a "casting down of every high thing that exalts itself against God" (2 Corinthians 10:4, 2 Corinthians 10:5).