Jeremiah's prophetic mission unfolds across a deeply turbulent historical and spiritual timeline, tracking the final years of the Kingdom of Judah through shifting leadership down to its ultimate collapse. His calling, which began during the reign of Josiah, continued steadily through the eras of Jehoiakim and Zedekiah, and likely spanned the brief rule of Jehoiachin as well [שטיינזלץ]. The word of God came to Jeremiah continuously until the completion of Zedekiah's eleven-year reign, marking the exact time the king was defeated by the ruler of Babylon [רד״ק].
This unbroken chain of prophecy highlights Jeremiah's dedication in the face of extreme social and spiritual instability. The moral climate of the nation fluctuated wildly. During Jehoiakim's era, the king was wicked, yet the general population remained righteous. By the end of Zedekiah's reign, the situation had completely reversed, with the people acting wickedly while the king himself was righteous [מלבי״ם]. Through all these shifting moral landscapes, Jeremiah steadfastly delivered his messages.
The defining era of his mission reached its climax with the exile of Jerusalem in the fifth month, known as Av, clarifying exactly when this period came to a close [מצודת דוד]. At this tragic juncture, all of Jeremiah's previous warnings and prophecies fully materialized [מלבי״ם]. Yet, while the exile serves as a major concluding marker for this timeline, his role did not entirely end there. He continued to deliver certain prophecies even after the kingdom was destroyed and the city was emptied of its people [שטיינזלץ].