2 Samuel 24:16-18

16When the [avenging] angel stretched out his hand toward Jerusalem to destroy it, the Lord relented from the disaster and said to the angel who destroyed the people, “It is enough! Now relax your hand.” And the angel of the Lord was by the threshing floor of Araunah the Jebusite.

17When David saw the angel who was striking down the people, he spoke to the Lord and said, “Behold, I [alone] am the one who has sinned and done wrong; but these sheep (people of Israel), what have they done [to deserve this]? Please let Your hand be [only] against me and my father’s house (family).”

18Then Gad [the prophet] came to David that day and said to him, “Go up, set up an altar to the Lord on the threshing floor of Araunah the Jebusite [where you saw the angel].”