Why does it discuss here hunger for Divrei Hashem?
Radak: They despised Nevu'ah from Hashem - "Lo Sinavei v'Lo Satif" (7:16). It says that days will come when they will thirst for Nevu'ah from Hashem, and not find it. These are all the days of Bayis Sheni after Nevu'as Mal'achi (Nevu'ah ceased then), and all the days of this Galus.
Malbim: This corresponds to when they will be fainting in Galus (13), because they did not want to hear Davar Hashem. It teaches that in the future there will be hunger and thirst, but not for food and water, like they had in Galus, rather, to hear Devar Hashem - in Bayis Sheni.
Where will there be hunger?
Radak: It will be in Eretz Yisrael. Just like one who is hungry or thirsty, he goes around to seek food or water (refer to 8:11:1:1).
Why will there be thirst to hear Divrei Hashem?
Rashi: Ru'ach ha'Kodesh will cease from you.
Malbim: Devar Hashem was dear (scarce) in Bayis Sheni. Vision was sealed after the last prophets. There was still Ru'ach ha'Kodesh among them, and they used Bas Kol (a voice from Heaven) (Yuma 9b). They sought Devar Hashem, and thirsted to hear His words.
