Which Jeremiah the prophet spoke refers back to “The word” in verse 1. For prophet see 1.5.

Die Bibel im heutigen Deutsch places verses 1-2 together, thus avoiding the parenthetical statement of Revised Standard Version and Good News Translation:

• Jehoiakim, the son of Josiah, was in his fourth year as king of Judah and Nebuchadnezzar was in his first year as king of Babylonia, when Jeremiah the prophet received his commission from the Lord to say to all the people of Judah and all the inhabitants of Jerusalem….

Quoted with permission from Newman, Barclay M. and Stine, Philip C. A Handbook on Jeremiah. (UBS Helps for Translators). New York: UBS, 2003. For this and other handbooks for translators see here .