What remnant is discussed?
Radak: It is what will remain after refining ? "u'Tzraftim ki'Tzrof Es ha'Kesef" (Zecharyah 13:9).
Malbim: The minority of Yisrael that will remain among the nations, and not go to Eretz Yisrael.
Who are the many nations?
Rashi: They will gather against Yerushalayim with Gog and Magog.
What is the comparison to dew?
Rashi: It does not come to the world via man. People do not request it from people. So Yisrael will not seek human help, only Hashem's help. Radak ? this is because Yisrael will be few, and there will be many against them ? [all will recognize] that only Hashem can save them.
Malbim: Yisrael that will remain among the nations will not receive influence via the nations, like they do now. Rather, they will be like dew, which comes [straight] from Hashem.
Why does it add "ki'Rvivim Alei Esev"?
Radak: Revivim are great rains. Esev (herbs) is bigger than Deshe (grass). So [Yisrael] will increase, and Hashem's good to them will increase.
Malbim: Rain makes herbs grow, and it does not benefit from the herbs. So Yisrael will influence good to the nations, and not receive from them, for they will not hope to get good and Chesed from people. They will receive all their influence from Hashem, without an intermediary.
Why does it add "Lo Yekaveh l'Ish"?
Radak: People do not hope to get it from people. The matter is repeated in different words.
Malbim: Refer to 5:6:4:2.
