Following King Amaziah's turn to idolatry, God’s anger is directed at him. In response, God sends an unnamed prophet to confront the king and rebuke him for the complete lack of logic in his actions [ביאור שטיינזלץ].
The prophet challenges the king's decision to seek out foreign gods. The astonishment in the prophet's message stems from a glaring contradiction. Not only did Amaziah commit a grave sin by worshiping idols in the first place, but he actively chose to adopt the very same idols that had just lost to him in battle [ביאור שטיינזלץ].
The prophet highlights the absurdity of this choice by pointing out that these gods completely failed to save their own followers from Amaziah's army. This presents the king with an obvious conclusion: the sheer inability of these idols to protect their own people is clear proof that they have no real substance and are not gods at all [מצודת דוד].