דברי הימים ב, פרק ל׳, פסוק י״ד

Preparing for the Passover sacrifice required a deep spiritual cleansing and the complete removal of idol worship from Jerusalem. This effort took place before the actual offering of the sacrifice [ביאור שטיינזלץ]. The need to purify the city first was strict: it is forbidden to give any part of the Passover sacrifice to someone who worships idols. Therefore, every trace of foreign worship had to be destroyed beforehand to make the people fit to eat the offering [מלבי״ם].

The cleansing operation was thorough. The people removed unauthorized altars that had been set up to worship God, as well as those dedicated to idol worship [ביאור שטיינזלץ]. They also cleared out specific items and locations associated with burning incense. The primary approach among commentators is that these were altars, tools, or designated spots used exclusively for burning incense to false gods [מצודת דוד, רלב״ג, ביאור שטיינזלץ]. However, another perspective suggests these were actually places where priests and Levites stayed [רש״י]. Ultimately, all of these altars and tools were completely cleared away and thrown into the Kidron Valley [ביאור שטיינזלץ].