What is "Fisas Bar"?
Rashi #1: Pisas is an expression of Pisyon (spreading) and increase.
Rashi (citing Kesuvos 111b): In the days of Mashi'ach, buns and silk garments will grow in Eretz Yisrael. (Rashi there - Pisas alludes to something of grain as big as a palm (Pas), and also to Kesones Pasim.) Also refer to 72:16:2:1.
Rashi #2: Pisas is an expression of satisfaction, like Piyus (appeasement). People are pleased with Hashem when He gives satiation in the world.
Radak: Refer to 72:16:2:3.
What is the meaning of "[b'Rosh Harim] Yir'ash ka'Levanon Piryo"?
(Kesuvos 111b): In the future, wheat will grow [tall] like palm trees "b'Rosh Harim". It will be easy to harvest - "its fruit [will rustle like trees of] Levanon." Hashem will bring a wind from His storehouse, causing the produce to fall. A person will take a handful from the field to feed his household.
Rashi (based on Vayikra Rabah 35:10): They are wheat kernels as big as tree fruits, like the Kelayos (kidneys) of a big ox. This was in the days of Shimon ben Shetach.
Radak: In the days of this king, there will be Brachah in the world. A man will seed a handful of grain, even on a mountain-top (which is not fertile), and the ears will be good and fat, and make noise when the wind blows on them, like trees of Levanon. "Piryo" is the yield of the handful of grain.
Malbim: The increase of grain will be on mountain-tops. The fruits will make noise like of Levanon, which has many branches - "v'Shav Levanon la'Karmel] veha'Karmel la'Ya'ar Yechashev" (Yeshayah 29:17). It will be on mountain-tops, for what used to be fields will now be cities 1 , and there people will sprout, just like grass sprouted there until now.
It seems that the text should say 'Arim' in place of 'Harim' (PF).
To whom does "Yatzitzu" refer?
Rashi: It refers to Yisrael.
What city is this?
Rashi: It is Yerushalayim.
Radak: (It is in all cities.) Just like vegetation will sprout in the fields, people will multiply in cities like grass.
