About what does he ask "until when"?
Rashi: Until when will they harden their hearts and not listen?
Radak: Until when will you block Teshuvah from them 1 ? They already received punishment for their sin. Will they receive more punishment?!
Malbim: Until when will I conduct with them like this, that I tell them to listen, and they do not understand? Will they forever be rebellious?!
What is the meaning of "Asher Im"?
Radak: Here, "Im" means Ki (when), like "v'Im Takriv Minchas Bikurim" (Vayikra 1:14) is like Ki Sakriv; "v'Im Yihyeh ha'Yovel" (Bamidbar 36:4) is like Ki Yihyeh. Here, it means until [the cities will be desolate]. "Im" is like "Asher"; The matter is repeated in a different word to strengthen it.
What will change when everything is desolate?
Rashi: They will not repent until punishments come on them and they go to exile.
What is the meaning of "Sa'u" and "Tisha'eh"?
Rashi: They are expressions of being barren and uninhabited. Radak - Sa'u is past tense used in place of future.
Why does it mention desolation of cities, houses and land?
Radak: A city is called desolate even if a few houses remain inhabited. The verse teaches that all the houses will be empty, and no one will work the land. This is like "veha'Adamah Lo Sesham" (Bereishis 47:19).
Malbim: First the cities will be destroyed, and individual houses will remain. Later, also the houses will be destroyed, and there will be no people, and there will be no shepherds and flocks. Afterwards, the land in general will be desolate.
