Adam Clarke on Isaiah 17:1

The burden of Damascus - Which is, according to the common version, The cities of Aroer are forsaken. It has already been observed by the learned prelate that the prophecy, as it relates to Damascus, was executed in the beginning of the reign of Ahaz, probably about the third year. If we credit Midrash, the Damascenes were the most extensive and flagrant of all idolaters. "There were in Damascus three hundred and sixty-five streets, in each of these was an idol, and each idol had his peculiar day of worship; so that the whole were worshipped in the course of the year." This, or any thing like this, was a sufficient reason for this city's destruction.

A ruinous heap - For מעי mei, "a ruinous heap," the Septuagint reads לעי lei, "for a ruin," the Vulgate כעי kei, "as a ruin." I follow the former.