Jeremiah 6:27-29

Revised Standard Version

²⁷ “I have made you an assayer and tester among my people,
    that you may know and assay their ways.
²⁸ They are all stubbornly rebellious,
    going about with slanders;
they are bronze and iron,
    all of them act corruptly.
²⁹ The bellows blow fiercely,
    the lead is consumed by the fire;
in vain the refining goes on,
    for the wicked are not removed.