1)
Why was Hashem with him?
1.
Malbim: It is because he trusted in Hashem.
2)
What is the meaning of "Yaskil"?
1.
Rashi: He succeeded.
3)
Why did he rebel against Melech Ashur?
1.
Radak: His father Achaz served him. Chizkiyah trusted in Hashem, and did not serve him. This is called rebellion. Malbim - Achaz needed Melech Ashur, for Melech Yisrael overpowered Achaz, and also Pelishtim invaded Yehudah. For Chizkiyah, it was the opposite - he rebelled against Melech Ashur!
