These verses, from 28 through 32, are a different prophecy, directed at the Philistines, rather than at Assyria or Babylon. While Palestine might rejoice with the destruction of the mighty foreign enemies, their time is also coming. Thus, they are told “rejoice not thou, whole Palestina, because the rod of him that smote thee is broken.” Isaiah declares that while that enemy will be defeated, yet a different destruction will come upon them. The Philistine pride will also be reversed.
Isaiah has used the imagery of howling multiple times in the descriptions of the destructions coming upon Israel. The Philistines will have their occasion to howl. They too will be brought down. The message is that in the last days, “the Lord hath founded Zion, and the poor of his people shall trust in it.” It will be the place where the wrongs will be made right, and the trodden poor brought to comfort and safety.