Reprobate - See the margin; not really silver, but the dross.
The Lord hath rejected them - This then is the end. The smelter is God’s prophet: the bellows the breath of inspiration: the flux his earnestness in preaching. But in vain does the fervour of prophecy essay to melt the hearts of the people. They are so utterly corrupt, that no particle even of pure metal can be found in them. All the refiner’s art is in vain. They have rejected all God’s gifts and motives for their repentance, and therefore Yahweh has rejected them as an alloy too utterly adulterate to repay the refiner’s toil.