Jeremiah 6:27-30

27“I [the Lord] have set you as an assayer [O Jeremiah] and as a tester [of the ore] of My people, That you may know and analyze their acts.”

28They are all the worst [kind] of [stiff-necked, godless] rebels, Going around spreading slander. They are [not gold and silver ore, but] bronze and iron; They are all corrupt.

29The bellows blow fiercely, The lead is consumed by the fire; In vain they continue refining, But the wicked are not separated and removed.

30They call them rejected silver [only dross, without value], Because the Lord has rejected them.