What is "k'Sukah v'Cherem"?
Rashi: It is empty of its residents. They were exiled from it. This is like a hut of the vineyard that the guard made, and when it is harvested, he leaves the hut. Targum Yonasan says 'after they harvest it.'
Radak: Most cities of Yehudah were desolate. In the days of Chizkiyah, Melech Ashur seized the fortified cities, and only Yerushalayim remained, like a hut in a vineyard and a shack in a gourd field. There is no other house or hut around. It does not mention a garden, for the guard is there the entire year. After they pick one species, another remains.
Malbim: The verses depict the decline of Tziyon level after level at these three times (refer to 1:7:6:3*). The first time, Yerushalayim remained alone, forsaken from the multitudes that always used to gather there 1 . Now, only its residents were in the city - like a Sukah in a vineyard, which only the guard resides in. Also refer to 1:8:2:1*, 1:8:3:1*.
Why was it bereft of its multitudes? The first time, Melech Ashur exiled the 10 tribes. From the start of Malchus Efrayim, guards stopped them from ascending to Yerushalayim. They were exiled in the days of Hoshe'a ben Elah, for he abolished the guards, and still people did not ascend (Tana d'Vei Eliyahu 9)! Perhaps people in Yehudah feared to ascend to Yerushalayim because Melech Ashur was nearby. (PF)
What is "ki'Mlonah v'Mikshah"?
Rashi: Like when the guard abandons the hut he made at the head of the patch to guard its gourds. After they are picked, he leaves. The shack in a vineyard is called Sukah, because he lives there day and night; during the day he guards from birds, and at night from thieves. Gourds are hard; there is no concern for birds. He guards only at night 1 . "Melonah" refers to lodging at night Yonason translates 'like lying in the lodging after Av'ayuhi 2 (they picked the gourds) from the patch.' Radak - so Tziyon was left without a guard. Hashem, Shomer Yisrael, removed His Shechinah.
Radak: Melonah is the same as Sukah.
Malbim: The second time that Melech Ashur came, people of Yerushalayim hid in caves and cavities in rocks during the day, due to the enemy, and they were in the city only at night. (We do not find that Sancheriv entered Yerushalayim! And if they entered the city every night, perhaps Machaneh Ashur would be able to enter when they opened the gates! Perhaps in Yerushalayim,people hid during the day, amidst fear lest Machaneh Ashur enter; only at night, they were seen in the city.
Rashi: This is like 'Shalosh Av'ayos (times to pick) b'Yom (Pe'ah 4:5). Radak - it is searching, like "Nav'u Matzpunav" (Ovadyah 1:6). After the grapes and gourds were picked, and they searched that nothing remained, the guard left.
What is the comparison to "Ir Netzurah"?
Rashi (from Targum Yonasan): This refers to a besieged city 1 . They make shacks around it to hide soldiers. When they depart, they leave the shacks.
Radak: This is a city desolate from its residents. This is like "uva'Netzurim Yalinu", "u'Netzurei Yisrael Lehashiv" (65:4, 49:6).
Malbim: This corresponds to the third time that Melech Ashur came, and he besieged Yerushalayim.
