Isaiah 33:21

The mighty king over this Zion will be Yahweh Himself, a divine ruler-even Messiah (cf. Isaiah 53:11).

"The meaning is, that, by virtue of Jehovah’s dwelling there, Jerusalem had become a place, or equivalent to a place, of broad streams, like those which in other instances defended the cities they surrounded (e.g. Babylon, the ’twisted snake,’ ch. xxvii. 1), and of broad canals, which kept off the enemy, like moats around a fortification." [Note: Delitzsch, 2:64-65.]