22:17-22 Israel, compared with other nations, had been as the gold and silver compared with baser metals. But they were now as the refuse that is consumed in the furnace, or thrown away when the silver is refined. Sinners, especially backsliding professors, are, in God's account, useless and fit for nothing. When God brings his own people into the furnace, he sits by them as the refiner by his gold, to see that they are not continued there any longer than is fitting and needful. The dross shall be wholly separated, and the good metal purified. Let those who suffer pains, or lingering sickness, and find that their hearts can scarcely bear these light and momentary afflictions, take warning to flee from the wrath to come; for if these trials are not sanctified by the power of the Holy Spirit, to the cleansing their hearts and hands from sin, far worse things will come upon them.

18. dross … brass—Israel has become a worthless compound of the dross of silver (implying not merely corruption, but degeneracy from good to bad, Isa 1:22, especially offensive) and of the baser metals. Hence the people must be thrown into the furnace of judgment, that the bad may be consumed, and the good separated (Jer 6:29, 30).