God is going to send Judah into exile under a foreign empire. Why would he cause such suffering? It’s because the people will not listen to him and that is exemplified in their sacrifices.
In the fire
Stop praying
Jeremiah has been poetically announcing the coming invasion of Judah and the resulting fall of Jerusalem, at the hands of a terrible army from the north. Why is this happening? Because, like the human race as a whole, the city has become contaminated by sins like lying.