Each of the nations represented by their envoys in Jerusalem had their own prophets, diviners, dreamers and fortune tellers who were saying the exact opposite of what Jeremiah was saying. They were all saying to their kings: You shall not serve the king of Babylon.
They were assuring their rulers that Babylonian dominance would soon end and the nations would be set free. But Jeremiah warns the envoys to tell their kings these voices are all speaking lies and that listening to them would result in the nations being driven out of their land and perishing, along with their false messengers. Ultimately, they were not resisting Nebuchadnezzar but the Lord, which would only end in judgment. This also highlights the danger of false prophets. They prevent people and nations from hearing the Lord’s word and responding positively in repentance.1
9 So do not listen to your prophets, your diviners, your dreamers, your fortune-tellers, or your sorcerers, who are saying to you, ‘You shall not serve the king of Babylon.’