The cities of Aro‛ĕr are forsaken, they are for flocks which shall lie down, with no one to frighten.

עֲזֻבוֹת עָרֵי עֲרֹעֵר לַעֲדָרִים תִּהְיֶינָה וְרָבְצוּ וְאֵין מַחֲרִיד

The cities of Aroer are abandoned: Jonathan renders this as an expression of destruction. Comp. ( Jer. 51:58) “shall be destroyed (עַרְעֵר תִּתְעַרְעַר) , and he explained it in reference to the cities of Aram, i.e., Jonathan renders it: Their cities are abandoned, they are destroyed. The Midrash Aggadah (introduction to Lam. Rabbah 10 [with variations], Yalkut Machin) asks in amazement, since Aroer was [part] of Eretz Israel, as it is said ( Num. 32:34) : ” and Aroer.“ He is dealing with Damascus and he announces matters concerning Aroer? But, since in Damascus there were streets as numerous as the days of the solar year, and in each one was a pagan deity, which they would worship one day in the year, and the Israelites made them all into one group and worshipped all of them every day, he, therefore, mentioned the downfall of Aroer juxtaposed to Damascus. I explain it, however, according to the simple meaning of the verse, as follows: Since Rezin and Pekah son of Remaliah joined together, and the prophet prophesying about the downfall of Damascus, and saying, ” Behold, Damascus shall be removed from [being] a city," and the cities of Aroer which belonged to Pekah were already abandoned, for the Reubenites and the Gadites had already been exiled, and they were always given to the flocks of sheep, and the sheep of Moab would lie there undisturbed, he continues to say that the kingdom of Pekah shall continue to be gradually terminated, and that Samaria, too, shall be captured in the days of Hoshea, and then (v. 3) And a fortress shall cease from Ephraim and a kingdom from Damascusfor Rezin shall be killed.