What is the source of the story about the melted gold in the destroyed temple in 70 AD? In Matthew 24:2, Mark 13:2 and Luke 21:6, Jesus seems to indicate that in the coming temple destruction, &quot;not one stone will be left upon another&quot;. And, indeed, this seems to be the case from the current ruins.
However, I have come across several commentaries that state that because the temple was burned, the gold that was on the walls, melted and ran between the stones, as well as into them.  The Roman solders then took stone from stone in a effort to retrieve the gold, thus giving literal fulfillment of Jesus' prophecy.
Having encountered this explanation several times in the course of my studies, I wanted to find the source for this story, but, as of this date, am unable to do so.  I don't find anything in Josephus relating to that gold-seeking activity.
Does anyone know of a source document or documents that can authenticate this story?
The Mystery of the Temple's 'Molten Metals'

Two recent apologists told the story, apparently independently, of molten gold seeping between the temple`s foundation stones during the Siege of Jerusalem in 70 CE.  Both implied the source was Josephus, but neither provided references.  Unfortunately, both had theological motivations for adding these details to their stories despite the lack of support.

On investigation, while much of their accounts of the destruction of the temple came from Josephus’ history – Jewish Wars 6.5.2, 6.6.1, 7.1.1, and 7.5.2 being particularly relevant – it seems the melted gold story did not.  It’s possible, however, the Christian apologists were duped by a medieval forgery into thinking it did.

Pastor Ray Stedman

The earliest example of the story I can find is Ray Stedman’s 1970 sermon on Mt.24:1-3, later published in a book.  Following on Jesus’ apparent prediction about the temple, that “there will not be left here one stone upon another,” Stedman told the story of the First Jewish-Roman War, suggesting his account was based on Josephus, including this:


  “There were great quantities of gold and silver which had been placed
  in the Temple for safekeeping. This melted and ran down between the
  rocks and into the cracks of the stones that formed the Temple and the
  wall around it. When the Roman soldiers finally took the city, in
  their greed to obtain this gold and silver they took long bars and
  pried apart these massive stones. Thus, quite literally, not one stone
  was left standing upon another.”


For Stedman, “this remarkable fulfillment, confirmed so strongly by secular history, is convincing proof” of the authenticity of Jesus’ prophetic message, “fully and literally.”  Though the story is unsubstantiated, Stedman’s telling of it is often quoted (and plagiarized).

Dr. Ernest Martin

Archeological enthusiast Ernest Martin told similar stories in his 1994 book, The Temples That Jerusalem Forgot, and in posts to his ASK website, including, ‘New Evidence for the Site of the Temple in Jerusalem.’  Martin’s controversial hypothesis was that Jerusalem’s temples were not on the Temple Mount platform (which he thought was the former Roman fortress) but on a now-destroyed foundation to the south.  His argument also emphasized Jesus’ phrase, ‘not one stone left upon another’, as well as genuine (and misquoted) passages from Josephus about the “utter ruin and thorough destruction of Jerusalem.”  In ‘New Evidence’ he wrote: 


  “Josephus explained the reason why every stone was overturned in the
  city (including those that made up the very foundations). The Jews
  were accustomed to hide their gold and other valuables in the walls of
  their homes. The Temple itself was also the treasury of the Jewish
  nation. [JW 6.5.2] When the fires consumed the whole of the Temple and
  City, the gold melted and descended into the cracks and crevices of
  the stone foundations. In order to recover this melted gold, the Tenth
  Legion had the Jewish captives uproot every stone of the Temple and
  the whole of the City. So much gold was discovered in this fashion
  that the price of the metal in the Roman Empire went down half of its
  pre-war value. [JW 6.6.1] This action of looking for gold by
  overturning the stones (including all foundation stones) left
  Jerusalem as a vast quarry of dislodged and uprooted stones in a state
  of unrecognized shambles.”


While the two footnoted sentences (and other bits) do comport with Josephus, the story about melted gold does not. His theory siting the temple on Ophel Mound rather than Temple Mount has not been embraced by scholars, but one can see why he’d need to emphasize the scope and greedy enthusiasm of the Roman destruction to explain the complete disappearance of the temple AND its entire foundation platform, as he imagined it.

Josippon?

An excited supporter of Martin’s theory has posted several quotes from his book online, and one offers a lead on the origin of the melted gold story (or not).  Martin is quoted as writing, “In regard to the total destruction of the temple and all its outer buildings, a Hebrew version of Josephus (known as Josippon) states ...”  And a few lines later: “And recall, Jewish authorities during the Middle Ages accepted this narrative of Josippon as that of Josephus, an eyewitness.”   The quote continues with another version of the melted gold story. 

The Jewish ‘history’ attributed to Josippon (aka Joseph ben Gorion, Yosippon, and Pseudo-Josephus) is regarded by modern scholars as a 10th century forgery (or pseudopigrapha).  Though it may have preserved some early Jewish folklore, the portion in question is actually believed to be the work of Pseudo-Hegesippus, the 4th century forger.   As history it’s quite unreliable.    

Regardless, given Martin’s penchant for weaving together sourced and non-sourced material in the same paragraph, it’s unclear (from the available quotations) whether he intended to credit the melted gold story to the dubious Josippon.  Martin's later essays retell the story without mentioning him.  Perhaps Josippon said noting at all about melted gold.  

So in the end we're left with a story that's either creative speculation, forged folklore, or unsubstantiated history – none of which counts as biblical scholarship.  Perhaps someone with access to Martin’s book or Josippon’s ‘history’ can provide more insights in the comments.