Matthew Poole and continuators on Isaiah 17:9

9 In that day shall his strong cities be as a forsaken bough, and an uppermost branch , which they left, because of the children of Israel : and there shall be desolation.

In the day of Iacob's Trouble, of which he spake v. 4. and continueth his Speech unto these Words, and afterwards.

Which he that pruneth the Tree neglecteth, either because he esteems it useless and inconsiderable, or because he cannot reach it.

The sence is, either, 1. Which they, to wit, the Enemies, left, or, which shall be left (the Active Verb being put Impersonally, as it frequently is in the Hebrew Text) because of or for the children of Israel; which God inclined their Hearts to leave or spare, out of his Love to his Israel. Thus this is mentioned as a Mercy, or Mitigation of the Calamity. But this seems not to agree either with the foregoing or following Words, both which manifestly speak of the greatness of the Judgment. And that their strong Cities were not left for them▪ but taken from them, seems evident from v. 3, 4. Or, 2. As the Cities (which Words are easily understood out of the former part of the Verse, where they are expressed) which they (to wit, the Canaanites, as the Seventy Interpreters express it; and it was needless to name them, because the History was so well known to them to whom the Prophet writes) left or forsook (which they did either by departing from them, or being destroyed out of them) because of (or before, or for fear of) the children of Israel. And this was a very fit Example, to awaken the Israelites to a serious belief of this Threatning, because God had inflicted the same Judgment upon the Canaanites, and that for the same Sins of which they were guilty.