What is "Afafu"?
Rashi: They surrounded. Radak - this is like "Afafuni Mishberei Maves" (Shmuel II, 22:5). Man is prone to mishaps without number. One should always fear lest sin cause [afflictions] (Brachos 4a), and even a Chasid, for "Ein Tzadik ba'Aretz Asher Ya'aseh Tov v'Lo Yecheta" (Koheles 7:20).
Why did he say "Hisiguni Avonosai"?
Radak: Mishaps occur only via sin (Shabbos 55a). "Hisiguni" means that they found me in the place of punishment; I cannot flee from them.
Malbim: This is why evils surrounded me. 'The snake does not kill; sin kills' (Shemos Rabah 3:12).
Why did he say "Lo Yacholti Lir'os"?
Radak #1: I cannot see all my sins, for they are many (more than the number of my hairs).
Radak #2: This is an exaggeration - my eyes dimmed and my heart is not with me, due to my fear over my sins.
Malbim: My eyes were plastered over, and I did not see that my sins afflict me, even though I should have seen, for they are so many.
What is the meaning of "Libi Azavani"?
Radak #1: My strength [abandoned me]. I.e. my Da'as abandoned counting them, for they are so many. It is proper for every Chasid, when praying to Hashem, to magnify his sins and minimize his merits. He should say that he is full of sins, and requests Kaparah and mercy.
Radak #2: Refer to 40:13:3:2.
Malbim: My heart did not perceive that evils come to me due to my many sins.
