Why did he say "Chatasi Mah Ef'al Lach"?
Malbim: Even if I sinned - what does it do to You? Does my sin harm You, and for this You take awesome vengeance?!
Why did he add "Notzar ha'Adam Lamah Samtani"?
Malbim: It cannot be that You guard me because You formed man, and guard him; You do not want to destroy Your handiwork. Why did You create me? There is no benefit from my existence.
What is "l'Mifga Lach"?
Rashi: It is like one who strikes when he is angry, and arouses his full anger.
Ibn Ezra: Your hand and blow strike me.
Malbim: It is something that its toil is greater than its benefit.
On whom is he a burden?
Rashi: The verse did not want to write on Hashem, so it writes euphemistically, as if Iyov is a burden on himself.
Malbim: On himself. It is a burden to bear the afflictions - non-existence is better than existence!
