1)
What time does this discuss?
1.
Malbim: It is after Resha'im will be cut off from Yisrael.
2)
Who will bring a gift, and what will it be?
1.
Radak: The nations will bring a gift with Yisrael to Hashem - "v'Hevi'u Es Kol Acheichem mi'Kol ha'Goyim Minchah la'Shem..." (66:20)
3)
Why is Har Tziyon called "Mekom Shem Hashem Tzevakos"?
1.
Radak: It is the place where He will be called "Shem Hashem Tzevakos."