Why does it say "v'Halchu? v'Amru Lechu v'Na'aleh"?
Radak: Every nation says to its fellow nation "Ki mi'Tziyon?" are the Navi's words, and not the nations'. I.e. why do the nations say "go and ascend? and He will teach us from His ways"? "Because from Tziyon will come Torah", and Mitzvah to all nations.
Malbim: Nations say to each other, go, and we will ascend with you to Har Hashem, and from there to the Beis ha'Mikdash.
Why is it called "Beis Elokei Yakov"?
Rashi (Yeshayah 2:3, from Pesachim 88a): He called it Beis Kel, therefore it is called on his name. Avraham called it "b'Har Hashem Yera'eh" (Bereishis 22:15), and Yitzchak called it a field ? "Lasu'ach ba'Sadeh" (Bereishis 24:63).
What is the meaning of "va'Yorenu mi'Derachav"?
Radak: Melech ha'Mashi'ach will teach us; it says about him "v'Shafat" (3).
Malbim: Derachim are the big roads. "Nelchah b'Archosav" ? we will go by ourselves on the small individual paths that branch off from the big roads. He will teach to us only the big paths 1 , which are the roots of the creed and its foundations, and we will strive to understand the details and branches.
Malbim: Also, he will teach to us only mi'Derachav (some of the big paths); via diligence, we will grasp all of [even the small] the paths.
What do we learn from "Ki mi'Tziyon Tetzei Sorah u'Dvar Hashem mi'Yrushalayim"?
Malbim: Tziyon was the place of the [great] Sanhedrin and those who rule about Torah law 1 . From there Torah goes to the entire world. Devar Hashem is Nevu'ah; Nevi'im are found in the entire city 2 .
Malbim (Yeshayah 2:3): "Ki Yipalei Mimecha Davar la'Mishpat... v'Kamta v'Alisa" (Devarim 17:8), i.e. to Tziyon.
I.e. they were not confined to a particular place in Yerushalayim, like the Great Sanhedrin was. (PF)
