What is the meaning of "Mi Yode'a"?
Rashi citing Targum Yonasan: One who knows that he has sins, will repent. Malbim - they are obligated to repent also for hidden sins. Just like they regret, Hashem will regret the decree.
Radak #1: Perhaps Hashem will retract when we repent from our evil deeds.
Radak #2: One who knows the ways of Teshuvah will repent 1 , and Hashem will retract.
If some did not know the ways of Teshuvah, those who knew them should have taught them! (PF)
What is the grammatical form of "v'Nicham"?
Radak: The Vov switches it from past to future; it is Nif'al.
Was the king sure that Teshuvah will avert the decree?
Radak #1: No.
Radak citing Targum Yonasan: Yes. Malbim - he understood that since Hashem sent a Navi, they can fix matters via Teshuvah.
