The coals inside the clay furnace begin to glow. After looking carefully inside, the smelter uses his bellows to puff air into the low flames. As the colors brighten, the heat intensifies. The large rocks beside him will ultimately be molded into tools, weapons, or containers, but not without the sustained, consuming heat that burns away their impurities. This is the metaphor the LORD uses to illustrate Israel’s enslavement in Egypt – the “iron furnace” mentioned in Deuteronomy and repeated later through the prophet Jeremiah.
The metaphor is part of a dire warning. The Israelites in Jeremiah’s time, now a divided kingdom, have descended into a depravity so deep it rivals that of Sodom. So, the LORD sends Jeremiah on a mission to preach repentance, but it falls on deaf ears. The coals of the LORD’s anger begin to glow, and Jeremiah’s prophecy is fulfilled within his own lifetime. His people will be taken into exile, eventually scattered, and the throne in Israel will never be re-established.
Jesus issues a similar warning to the Israelites of his time, who, like their ancestors, make the temple serve them, rather than serving the LORD within it. Yet again, the furnace awaits. Not one of those impressive temple stones, Jesus says, will be left on top of another. It would take less than forty years for that prophecy to be fulfilled.
Jesus also warns us about the end of the age. As in Jeremiah and Jesus’ time, the days will be dark, and the wicked will ridicule those whom God sends. In fact, the days will be so evil that we would destroy ourselves if God would not put an end to them.
But the iron furnace is not our ultimate fate. The temple of Jesus body has been destroyed and raised again, and through water – not fire – he has put the calloused sinner to death and raised us into worthy servants. He does not scatter us, but gathers us together around him as his people. He graciously extends the call of his prophets across the centuries to us for the forgiveness of sins. The days are no less dark, but the light has already come into the world. Our salvation is at hand. Hear his Word and rejoice!