Who found the Chacham in the city?
Rav Sadya Gaon: He was found there.
What is "Misken"?
Rav Sadya Gaon: It is poor. Ibn Ezra - this is an adjective. The noun is "Miskenus" (Devarim 8:9). The Mem is added (it is not from the root). We find this in Arame'ic 1 .
Magihah (in Toras Chayim): The Targum of "v'Im Ish Oni Hu" (Devarim 24:12) is v'Im Gevar Misken Hu.
What is the Nimshal of the poor Chacham?
Rashi citing Nedarim 32b: This is the Yetzer Tov. R. Avigdor - no one listens to him. Anyone who listens to the Chacham is saved from Gehinom.
Ibn Ezra: This is not a Mashal. It truly discusses a Chacham who saved a city. Above (6:8), he said "Mah le'Oni Yode'a" - even though usually, his Chachmah does not help us in this world, sometimes it helps more than the kingdom.
Seforno: So Chachmah of an Oni can defeat Ma'areches ha'Melech that fights against him, and chance occurrences.
Malbim (Mishlei 21:22): Chachmah saves the Nefesh, that the old fool will not conquer it.
How did he save the city with his Chachmah?
Nedarim 32b: This is a Mashal for repentance and good deeds.
Rav Sadya Gaon: It was with his conduct and Chachmah.
Why does it say that no one remembered the poor Chacham?
Nedarim 32b: When the Yetzer Ra entices, no one remembers the Yetzer Tov.
Rav Sadya Gaon: No one remembered him, and no one knew him.
Rashi: No one esteemed him at all.
Ibn Ezra #1: There was no mention of him before he saved the city 1 . Some say that Zachar 2 and Yizkor are always in the heart; "Azkirah" (Tehilim 45:18), a Kaved conjugation, is in the mouth.
Ibn Ezra #2: Sometimes Zechirah is in the heart, and sometimes it is in the mouth - "u'Masa Hashem Lo Sizkeru Od" (Yirmeyah 23:36) is in the mouth. Why would the verse say that the heart will not remember Masa?
Rashbam: Refer to 9:14:1:2.
R. Avigdor citing Koheles Zuta: Hashem said, you did not remember him. I will remember him - "v'Hasirosi Es Lev ha'Even mi'Besaram" (Yechezkel 11:19).
Metzudas David: Therefore, it is wondrous that Chachmah alone saved the city. Had he been esteemed, we could say that his esteem helped with his Chachmah.
Ibn Ezra: They needed to say that "v'Lo Zachar Sar ha'Mashkim" (Bereishis 40:23) - it did not cross his heart; "va'Yishkachehu" (ibid.) is a repetition. My Perush is better (refer to 9:15:5:5).