דברי הימים ב, פרק כ״ד, פסוק י״ח

Abandoning traditional faith often leads to replacing sacred worship with something foreign and physical. When the people turned their backs on God and left the Temple, the direct result was a quick fall into idolatry [מצודת דוד]. They began worshipping trees set aside for rituals, as well as carved figures, engaging in practices that carry a deep sense of shame [ביאור שטיינזלץ].

The root of this spiritual failure was very specific. The people decided to treat their own king as a god [מלבי״ם]. They made statues that looked exactly like him and planted sacred trees in his honor. Even though they did not take up the familiar foreign gods of the surrounding nations, worshipping a human leader was still considered complete idolatry. Because of this guilt, intense Divine anger was directed at Judah and Jerusalem [מצודת דוד, ביאור שטיינזלץ]. It was this deliberate choice to worship the king that ultimately brought about the anger of God [מלבי״ם].