Charles Ellicott Commentary Isaiah 1:25

"and I will turn my hand upon thee, and thoroughly purge away thy dross, and will take away all thy tin;" — Isaiah 1:25 (ASV)

I will turn my hand upon you. —The phrase, like the English “visit,” presents both a severe and a gracious aspect. Of the former we have instances in Psalm 81:14, Amos 1:8; of the latter in Zechariah 13:7. The context here inclines to the latter meaning. Jehovah punishes so that He may save, and strikes so that He may heal.

Purely purge away your dross. —Better, will smelt away your dross with lye, or potash, which was used in the smelting process. The imagery of Isaiah 1:22 is resumed. The great Refiner can purify the debased metal. In Malachi 3:2-3, we have the same image expanded. The process involved, of course, the rejection of the dross—i.e., in the interpretation of the parable, of the lead that would not let itself be turned to silver.

Tin. —Better, perhaps, lead. In either case, Isaiah’s knowledge of metallurgy was probably due to interaction with the Phoenicians, who brought both lead and tin from Tarshish (i.e., Spain).