Radak #1: This is like Chemah b'Apo.

Radak #2: It is Samuch, as if it says Chemas Apo. We find like this - "k'Eifah Se'orim" (Rus 2:17), "Asefah Asir" (above, 24:22).

Radak: This is the full form of Az (power), like "v'Ezuzo v'Nifle'osav" (Tehilim 78:4); usually, the second Zayin is omitted.

Rashi: Other nations, in order that Yisrael be chastised - "Hichrati Goyim Nashamu Pinosam

Rashi: [Yisrael] knew, but was contemptuous, and was not concerned to understand and repent from his evil.

Radak: He did not know that this was due to his sins, and he should repent to make the evil depart.

Malbim: When the enemy destroyed cities on the borders of Yisrael, Yisrael thought that they are b'Shalom.

Rashi: After the Nochrim around him were punished, the fire burned [Yisrael] himself.

Radak citing his father: This is when Sancheriv's army came to Yerushalayim.

Malbim: Even after the fire (war) began to burn [Yisrael], he did not think to extinguish it and repent to Hashem.