Why did he ask to seek Hashem on behalf of himself?
Rashi: He saw written in the Torah "Hashem will take you and your king [to exile]" (Devarim 28:36).
What is the meaning of "Nitzesah Vanu"?
Radak: It is ignited against us, like "Hineni Metzis Becha Esh" (Yechezkel 21:3).
Here it says "k'Chol ha'Kasuv Aleinu." Why does it say in Divrei ha'Yamim II, 34:21 "k'Chol ha'Kasuv Al ha'Sefer ha'Zeh"?
Malbim #1 The Torah, which is written on a parchment with ink, is written also on the tablet of the heart and engraved on the Nefesh. This is like I wrote about "bi'Megilas Sefer Kasuv Alai" (Tehilim 40:8. A person's intellect and emotions obligate him.)
Malbim #2: "K'Chol ha'Kasuv" refers to Hashem's anger. It is ignited against us in the curses in Ki Savo, because we did not heed this Sefer.