Following his introductions about the sins of Yehuda, Yirmiyahu begins to issue a more direct warning about the impending calamity. He calls on the people of Yehuda to sound the alarm: "’Sound the ram’s horn in the land.’ Call out loudly and tell one another, ‘Let us gather and enter to the fortified cities’" (4:5). He urges them to gird themselves with sackcloth and ashes in preparation for the desolation that the enemy will bring.

Amidst these warnings, Yirmiyahu implores the people of Yehuda to repent. But what is the significance of his call for repentance now? And how does it differ from the repentance he emphatically rejected in Chapter 2: "Although you wash yourself  with natron and heap soap on yourselves, your guilt is stained before Me, declares the Lord God" (2:22)?

The key lies in the guideword of this chapter — the ‘heart’. The term "heart" appears seven times in this chapter: in Yirmiyahu's plea for the people of Yehuda to return to God: "Men  of Yehuda and inhabitants of Jerusalem: Circumcise yourselves before the Lord, and remove the hardness of your hearts” (4:4), and "Jerusalem: Cleanse your heart from evil so that you will be saved" (4:14); in the description of the calamity: "On that day – declares the Lord – the king will lose heart, and so shall the heart of the princes fail” (4:9), and "This is your punishment so bitter. It has touched your very heart” (4:18); and in Yirmiyahu's lament: "My innards, my innards quake, as do the chambers of my heart. My heart pounds; I cannot stay silent" (4:19).

This is the stark difference between the futile cleansing described in Chapter 2 and the effective transformation Yirmiyahu calls for in this chapter: "Cleanse your heart from evil." (4:14) This is not an external cleansing. It is not an attempt to wash away stains superficially while proclaiming, "you were never defiled" (2:23). Rather, it is a profound, internal process of repentance — a genuine transformation that involves seeking God and correcting one’s ways. God desires the heart. When we return to Him wholeheartedly, His promise will be fulfilled: "If you, Israel, return to Me, declares the Lord, I will welcome your return" (4:1).