Isaiah 1:25

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

Purely purge away thy dross.—Better, will smelt away thy 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 intercourse with the Phœnicians, who brought both lead and tin from Tarshish (i.e., Spain).