Why does the Lord say that he rescued his people “from the iron furnace” so that he may “give them a land flowing with milk and honey, as at this day”?

 Smelting iron requires very high temperatures in an iron furnace. This image is often used in Scripture to describe times of extreme misery (see Deuteronomy 4:20; Deuteronomy 7:8; Deuteronomy 8:18; Deuteronomy 26:8–9; Deuteronomy 31:20; 1 Kings 8:51; Ezekiel 22:18–22; Isaiah 48:10). The people of Judah must understand that the Lord had rescued their forefathers from a desperate situation of misery in Egypt. Having brought them out he called Israel to covenant faithfulness at Mt Sinai so that I may confirm the oath that I swore to your fathers, to give them a land flowing with milk and honey. The Lord had promised Abraham, Isaac, and Jacob that he would give their descendants a land of their own (Genesis 15:18; Genesis 17:8; Genesis 35:12; Exodus 3:17). At Sinai he commits himself again to that promise, but the phrase that I may highlights the fact that taking possession of the land depended on covenant faithfulness. Jeremiah is to say all of this to remind the people of Judah just how important covenant faithfulness is.¹ Jeremiah’s message ends with the words, as at this day. The people of Judah are currently in the land of milk and honey, but the terms of the covenant have not changed and the great danger they face is being driven out because of their unfaithfulness to the covenant.