Humility and the admission of guilt have the power to alter divine judgment. When a nation recognizes the justice of its punishment, God transforms absolute destruction into measured, educational correction. By humbling themselves, the people essentially admit that their suffering is a justified consequence of their sins.
In response to this sincere admission, God draws a clear distinction between a punishment meant to destroy and one meant to heal. A destructive penalty stems from deep, inner anger and resentment. A healing correction, however, is like a father disciplining his son. Outwardly, God may show an angry face, but in His heart, He loves the people and seeks only their ultimate good [מלבי״ם].
Because of the people's submission, God makes two critical promises. First, a small remnant will be saved. Had the people not repented, no one would have survived [מלבי״ם, מצודת דוד, מצודת ציון]. Instead, they are granted a limited rescue, ensuring that the monarchy will continue to exist [ביאור שטיינזלץ].
Second, God promises that His destructive inner anger will not be poured out upon Jerusalem through Shishak, the king of Egypt [מלבי״ם, מצודת ציון]. In practical terms, this means that while the city will still be looted by Shishak as a necessary consequence, it will not be reduced to a wasteland or completely destroyed by his hands [מצודת דוד, ביאור שטיינזלץ].