What is the meaning of "va'Achashevah Lada'as Zos"?
Rashi: I thought in my heart to know this Midah of Hashem.
Radak: I was afraid to say with my mouth like they tell with their mouths, that Hashem does not know (verse 11).
Malbim: If I will not tell the Rabim, just I will think about this investigation by myself, also this is unjust in my eyes. It looks like I am unsure about a fundamental of Emunah!
Why did he say "Amal Hu v'Einai"?
Rashi: This Midah seemed to me unjust, and not Mishpat.
Radak: It was unjust in the eyes of my heart. I could not resolve it.
Why is it written Hi, and we pronounce it Hu?
Radak: The Kesiv refers to the claim and answer (feminine); the pronunciation refers to the matter (masculine); they are the same.
