Charles Ellicott Commentary Jeremiah 11:3

"and say thou unto them, Thus saith Jehovah, the God of Israel: Cursed be the man that heareth not the words of this covenant," — Jeremiah 11:3 (ASV)

Cursed be the man ... —The verse is, as it were, a mosaic, so to speak, of phrases, with slight verbal changes, from the recently discovered book of Deuteronomy—the iron furnace from Deuteronomy 4:20 and 1 Kings 8:51, Hear my voice and do them from Deuteronomy 28:1, and You shall be my people from Deuteronomy 29:13. The iron furnace was, of course, Egypt, the furnace of affliction, as in Isaiah 48:10, in which the people had endured sufferings of which that was the only adequate symbol. The word used denoted the “furnace” of the smelter, but the actual form of bondage through which the Israelites had passed, working in the brick-kiln furnaces (Exodus 1:14), had probably given a special force to the phrase.