There are two vital issues that should not go unnoticed in this book about a rebellious people and their certain judgment. First is the fact that judgment does come. Its final execution with all its force may be put off and put off and put off, as God waits patiently for repentance (see 2 Peter 3:3-13). But wrath will come, if repentance does not.
A second vital issue to recognize is that of the human heart. Judgment finally fell upon Judah - God finally stopped waiting for repentance - because the collective hearts of the people had hardened to the point of no return. Their hearts had become like stone; immovable and unmoldable. Their hearts were beyond cure (Jeremiah 17:9). Only judgment was left for the people of Judah.
The writer of Hebrews warns us not to risk this same hardness of heart (Hebrews 3:13). He warns us not to become hardened by sin's deceitfulness. Sin does that. It hardens your hearts against God.
When you read Jeremiah, notice how frequently he speaks of the heart. And look to your own heart and ask: Is my heart responsive to God, or growing hard?