Jerome : (Verse 31.) Howl, O gate! Cry out, O city! Philisthaea is laid waste, all of it. For from the north comes smoke, and there is no escaping its horde. He calls the gate for those who are at the gate, and the city for the inhabitants of the city. He also directs his speech to the cities of the Philistines, saying that they should wail and mourn when Senacherib comes, and when the torrent ravages everything. For the Assyrian came under the reign of Hezekiah, and among other nations he devastated the Philistines. To whom Jeremiah speaks: Behold, waters rise up from the north, and they shall be like a overflowing torrent, and they shall cover the land and its fullness, the city and its inhabitants (Jer. 47:2). For from the north comes the Assyrian, and from its heat, they go forth, subjugating Nineveh and other nations. At that time when these things were being sung, smoke rose up on high, that is, a rumor spread among the peoples in the order of all nations, that the Phoenicians and the Philistines were also to be devastated. — Commentary on Isaiah