Araunah the Jebusite's threshing floor is the site of the altar the LORD had Gad tell David to build during the three-day plague in Israel. It was also where David saw the angel striking the people. (2 Samuel 24:16-25)
Araunah sells his threshing floor to King David
Gad told David, “Go up, raise an altar to the Lord on the threshing floor of Araunah the Jebusite.” When Araunah looked down and saw the king and his servants coming up. He went and paid homage to David with his face to the ground. “Why has my lord the king come to his servant?”
David said, “To buy the threshing floor from you, in order to build an altar to the Lord, that the plague may be averted from the people.”
Araunah responded, “Let my lord the king take and offer up what seems good to him. Here are the oxen for the burnt offering and the threshing sledges and the yokes of the oxen for the wood. All this, O king, Araunah gives to the king.” And Araunah said to the king, “May the Lord your God accept you.”
David responded, “No, but I will buy it from you for a price. I will not offer burnt offerings to the Lord my God that cost me nothing.” So David bought the threshing floor and the oxen for fifty shekels of silver. And David built there an altar to the Lord and offered burnt offerings and peace offerings. So the Lord responded to the plea for the land, and the plague was averted from Israel.