Why does it repeat "since they were humbled"? Verse 7 already said so!
'Rashi': It is repeated because there was an interruption.
Malbim: The first humility was when the oppressor was in the land. It did not suffice to avert Hashem's Af that He not punish at all; it averted only the Chemah. They remained slaves to Shishak. Now Rechav'am was truly humbled; the shields constantly reminded him to be humble. This averted also Hashem's Af, and redeemed them from serving Shishak.
What is the meaning of "Lo Lehashchis"?
Metzudas David: He will not totally destroy them.
Malbim: Sometimes Hashem's Af (punishment) is averted for the sake of destruction, so the sinner can fill his measure of sin and be totally destroyed. Here Hashem's Af was totally averted.
