This is giving mercy to Israel in the destruction of the Assyrian, compare chapters 15, 16, Micah, and the subjection of all Philistia. Note, in remarking on Babylon, the different things which are assembled in that prophecy.
The subjection of Moab seems to be, according to the statement of the Psalm, the work of Messiah, after the destruction of the adversary, in whose exaltation Israel has rejoiced, or at least was joined with the Assyrian. They are called on to receive the outcasts during the oppression of Antichrist, anticipating his destruction, or showing their folly in not owning it by his destruction.
8. Meaz (A.V., " since ") seems to mean "from of old."
13 and 14 seem to have a special application.