What should he hit with his palm?
Radak #1: He should clap his hands, like "va'Yispok Es Kapav" (Bamidbar 24:10).
Radak #2: He should bang his thigh, like "Safakti Al Yarech" (Yirmeyah 3:18).
What is "u'Rka b'Raglecha"?
Rashi: Context shows that it is stomping his foot on the ground and flattening the mud. It is the way of mourning.
Radak: He bangs one foot against the other. It is as if he flattens and spreads out the land under him.
Why did Hashem tell him "Hakeh b'Chapcha u'Rka b'Raglecha"?
Malbim: It is amidst anger over the evil abominations of Beis Yisrael. Even so, Yechezkel should rejoice over their punishment (refer to 6:11:4:2).
What is "Ach"?
Rashi: It is screaming agony and woe.
Malbim: It is Simchah 1 that Hashem will punish them, and they will fall via hunger, sword and plague.
Elsewhere we find that it is an expression of Simchah, e.g. "Amar ha'Oyev Aleichem he'Ach" (36:2). (PF)
What is the grammatical form of "To'avos Ra'os Beis Yisrael"?
Radak: It is Samuch to Samuch 1 , like "Mispar Mifkad ha'Am" (Shmuel II, 24:9), "Nahar Nachalei Devash v'Chem'ah" (Iyov 20:17).
I.e. a triple compound noun. (PF)
What is the meaning of "Asher ba'Cherev ba'Ra'av?"?
Radak, Malbim: That in the punishment for the abominations, they will fall via hunger, sword and plague.