What are the "Tochachos"?
Rashi: They are punishments written in the Torah for our sins; You afflicted us with them.
Radak: So is Your way to afflict people with rebukes for their sins, like You did to me - 'v'Huchah b'Mach'ov Al Mishkavo" (Iyov 33:19).
Why does it say "b'Sochachos Avon Yisarta Ish"?
Malbim: Normally, Tochachos are verbal, and Musar us via afflictions. It would have been proper that You rebuke us for sin with Tochachah of love, and gently. Rather, You afflicted man with afflictions. These are due to Hashgachah, and not due to nature.
What is the meaning of "va'Temes ka'Ash Chamudo"?
Rashi: You made our flesh rot like a garment eaten by moths. Chamudo is his flesh - his treasured matter.
Radak: You melted Chamudo, i.e. the fat of his flesh and the strength of his body. Just like moths quickly consume a garment, so You melt a person via afflictions - "Yichel Besaro me'Ro'i" (Iyov 33:21).
Malbim: Via the afflictions, also Chamudo, i.e. the Nefesh, will melt and be finished.
Why did he say "Ach Hevel Kol Adam"?
Radak: Chamudo (his fat and strength) will pass, as if it is not.
Malbim: If afflictions will finish, if so every man is Hevel, for, he will not attain the purpose for which he was created.
