1)
Why does it say "v'Rinenu Al Bavel Shamayim va'Aretz"?
1.
Radak: It is as if Shamayim and Aretz will rejoice and sing over its fall.
2.
Malbim: I will bring evil on Bavel via Hashgachah, and also the Ma'arachah in Shamayim and natural processes in the land will obligate its fall.
2)
Why does it say "Ki mi'Tzafon"?
1.
Malbim: The Ma'arachah will obligate that they come from the north.
