Jeremiah 6:28

They are all grievous revolters, walking with slanders: they are brass and iron; they are all corrupters.

The verse identifies the people as grievous and entrenched rebels rather than occasional offenders. Their rebellion expresses itself in constant movement among others as carriers of slander. By that talebearing they act as corrupters, spreading moral ruin wherever they go. The figure of brass and iron denotes an inner hardness that refuses to be softened or corrected.