A number of interpretations have been suggested for Jeremiah 15:12. Iron from the Black Sea area in the north was known in later Greek and Roman records as having the best quality and so two possible ways of understanding the verse are as follows:
Jeremiah need not fear that the Lord’s prophecies will be fulfilled. Human opposition will not break the iron of the Lord’s word.
The iron from the north represents the invading enemy and Judah will not be able to stand against it. Judgment will come no matter how much it is resisted.1
Whichever interpretation is chosen the main idea seems to be that regardless of how strong the resistance is to Jeremiah’s message; in the end the Lord will do what he has said he will do through his prophet. The Lord’s word will prevail and therefore the Lord’s prophet will be vindicated.
12 Can one break iron, iron from the north, and bronze?