What is the consequence of "Ya'an Asher Hichrati Mimech?"?
Rashi: I knew that when the Nochrim will rejoice at your downfall, I will get angry at them and incite Nebuchadnetzar on all of them ? "v'Nitzrevu Vah Kol Panim" (3) of the south.
Radak: I took great vengeance against you, and your enemies rejoiced over you, and helped Me [to do evil to you] too much. Therefore, all of them will be stricken, like you were stricken ? therefore, "Tetzei Charbi mi'Tarah."
Malbim: Just like I cut off from you first the Tzadik, and afterwards the Rasha, and only the dry trees will remain, therefore the flame will not be extinguished; therefore My sword will leave the case from south to north. From Eretz Yisrael it will return to the nations that dwell in the north. After [Nebuchadnetzar] conquered Yerushalayim, he conquered all the neighboring nations, and inundated also the Jews who escaped to there.
Why does it say "El Kol Basar"?
Radak: This is like Al Kol Basar. There are many verses like this. Kol Basar is the nations about whom the Nevi'im prophesized.
Why does it say "mi'Negev Tzafon"?
Radak: This is like I explained above (3, mi'Negev Tzafonah). Just like My sword will cut you off from south to north ? you will be exiled there (in the north), and you will be cut off via the king of [Bavel, in] the north, so the other nations will be stricken via him, afterwards he will be stricken via Madai and Paras.
Malbim: The fire began to consume in the south; it will spread to the north.