The background narrative about the selection of the site for Solomon’s Temple provides some more interesting bits of evidence on its location. Near the end of his life David decided to conduct a census of his kingdom (2 Sam 24; 1 Chr 21). But the angel of death appears and a plague sweeps over Israel (2 Sam 24:10-15). The angel stands on the “threshing floor of Araunah the Jebusite” preparing to destroy Jerusalem with this plague, but God stops the angel and saves Jerusalem (2 Sam 24:15-17). (Note that according to 2 Chr 3:1 this is site is equated with Mt. Moriah, where Abraham was prepared to offer his son Isaac as sacrifice, but was stopped by the Lord (Gen 22:2, 14). The incidents were obviously meant to be parallel, where the Lord saves Isaac on the one hand, and Jerusalem on the other.) David is ordered to build an altar and offer sacrifice on the site of “the threshing floor of Araunah the Jebusite” where the Lord appeared and saved Jerusalem from destruction (2 Sam 24:18), which he does. This is the site upon which the Temple will eventually be built (2 Chr 3:1)
No specific details are given about the location of Araunah’s threshing floor, but several hints are provided. 2 Chr 3:1 states that Solomon built the Temple “on Mount Moriah, where the Lord had appeared to his father David. It was on the threshing floor of Araunah the Jebusite.” First, note that the location is on a mountain, a har in Hebrew. This certainly matches the geography of the Temple Mount, but Silwan is a ridge attached to the higher mount, and is lower in elevation than the Temple Mount itself.
An understanding of the nature of the ancient threshing process can also help us envisage its location. Threshing in the process of separating the grains of wheat from the stalks and sheaves, of chaff that contain it. It was often done by beating, stamping, or dragging weighted sledges over the stalks of wheat or barley. Once the stalks were separated from the grains, the result was a mixture of grain and dry chaff, which needed to be further separated by the winnowing process, since the chaff is inedible to humans. This usually involved taking the mixture of grain and chaff, throwing it into the air on a windy day, and letting the wind blow the light chaff away, while the heavy grains fall back to the earth. This process is generally undertaken in high places with direct exposure to a strong wind. Inside Jebusite Jerusalem on the Silwan ridge, the power of the wind would have been constrained by both the higher ridges to the north, west, and east, and by the walls of the city. Having a threshing floor inside a city wall, below a larger hill that would serve as a windbreak would make no sense from an ancient point of view. On the other hand, a rocky outcrop on the undeveloped top of a hill directly exposed to the wind would have been an idea place for a threshing floor.
Another important hint is provided by the story of David paying for the threshing floor. Araunah offers to give King David the site for free (2 Sam 24:19-23). But David refuses the offer, insisting: “I will buy them from you at a price. I cannot sacrifice to the Lord my God burnt offerings that cost me nothing” (2 Sam 24:24). David emphasizes that the site of the future Temple must be paid for; that is to say, the offering to the Lord must come from David himself, not from something others have given to him. Now, if the Temple were built within the city walls of old Jebusite Jerusalem, it would have necessitated the purchase and demolition of a number of houses that were already there. But no mention is made of purchasing other houses, nor of their confiscation or demolition, even though this type of activity was condemned by the biblical authors (e.g. 1 Kgs 21 where Ahab is condemned for confiscating the vineyard of Naboth.) The account implies that purchase of the threshing floor of Araunah provided sufficient space to eventually build the Temple. This would make sense if it were an empty rocky outcrop such as the Temple Mount was at that time, but would not make sense if the location were inside a densely populated Middle East city.