What is the significance of striking His palm?
Rashi: I screamed 'woe' and lamented.
Radak: This is a Mashal ? like a man who is pained, 'Akeh Chapi El Kapi" (21:22).
Radak citing Targum Yonasan: I will punish you.
Malbim: This is the final verdict, that Nebuchadnetzar will destroy Yerushalayim.
What do we learn from "El Bitz'ech"?
Rashi, from Vayikra Rabah 33:3: Theft is worse than all the Aveiros (Radak ? all 24 listed); the decree was sealed due to it. Malbim ? also Dor ha'Mabul's decree was due only to theft.
Radak: This is like Al Bitz'ech.
Targum Yonasan: For liability of money that you extorted from your victims. Radak ? i.e. they took from who lack power to escape from those [extortionists].
Why does it say "Damech" (singular) and "Hayu" (plural)?
Radak: The singular is for the Klal. The plural is because they spill much blood.