What is the meaning of "Nischaf"?
Rashi: [Your Giborim] were inundated and slipped. This is like "Matar Sochef" (Mishlei 28:3), 'Nistachpah Sadehu' (Kesuvos 12b).
Rashi citing Menachem: It is an expression of eradication. He explained "Matar Sochef 1 " (Mishlei 28:3) similarly.
Rashi: Dunash explained "Matar Sochef" like Matar So'ef; this is like "Mesa'ef Purah b'Ma'aratzah" (Yeshayah 10:33 - cutting off the branches).
Why does it say "Nischaf (singular) Abirecha (plural) Lo Amad (singular)"?
Radak: It applies to each one of your mighty ones.
What is the meaning of "Lo Amad"?
Radak: [It is as if rain inundated him so much that] he cannot stand [by himself].
Malbim: They did not stand in war in the fortified cities.
