1)
When will many nations come?
1.
Radak: It will be in the days of Mashi'ach. "Od" means still, like "Od ha'Yom Gadol" (Bereishis 29:7), "Od Oshivecha va'Ahalim" (Hoshe'a 12:10).
2.
Malbim (20, 22): It will be in the end of days. There will be two stages. (a) Close to the time of Ge'ulah, all nations will recognize that Yerushalayim is Ir ha'Kodesh - each man according to his Emunah. The Notzerim and Yishmaelim consider it Ir ha'Elokim and go there to pray. Shortly before the Ge'ulah, all nations will go to Yerushalayim and seek Hashem, i.e. the cornerstone of Emunah. Even though Yisrael will be lowly in their eyes, nations will seek the matter in Yerushalayim. We find this already in our days!
