What are "Devarai v'Chukai"?
Radak: Chukai are My decrees on you, that you will die via the sword, hunger and plague, and the rest will be exiled.
What do we learn from "Asher Tzivisi Es Avadai ha'Nevi'im ha'Lo Hisigu Avoseichem"?
Radak: Every punishment prophesized for your fathers came true. They repented and confessed at the time of the Churban.
Sanhedrin 105a (according to Ben Yehoyada): Zecharyah replied, when the punishments prophesized for your fathers came true, they repented and admitted that they were worthy of it, so they have a share in the world to come. You do not repent! "Va'Yashuvu va'Yomru..." - they admitted that Zecharyah was right.
Malbim: You do not need a Navi to predict what will come for your sins. They already came, and still exist! You were not yet redeemed from Koresh's Reshus. You recognize His Hashgachah and punishment, and You saw that He has the ability to punish sinners.
What do we learn from "ki'Dracheinu uch'Ma'alaleinu Ken Asah Lanu"?
Malbim: They admitted that the punishment was Midah k'Neged Midah. There is no more need for Nevu'ah, for their eyes were opened to know Hashem's deed.
