Gad came to David that day and said to him, "Go up and set up an altar to the Lord on the threshing floor of Araunah the Jebusite."
2 Samuel 24:18 In-Context
When the angel stretched out his hand to destroy Jerusalem, the LORD relented concerning the disaster and said to the angel who was afflicting the people, “Enough! Withdraw your hand.” The angel of the LORD was then at the threshing floor of Araunah the Jebusite.
When David saw the angel who was striking down the people, he said to the LORD, “I have sinned; I, the shepherd, have done wrong. These are but sheep. What have they done? Let your hand fall on me and my family.”
On that day Gad went to David and said to him, “Go up and build an altar to the LORD on the threshing floor of Araunah the Jebusite.”
So David went up, as the LORD had commanded through Gad.
When Araunah looked and saw the king and his officials coming toward him, he went out and bowed down before the king with his face to the ground.