1 Chronicles 21:15-19

And God sent an angel to Jerusalem to destroy it; but as he was about to destroy it, the Lord saw and was sorry about the catastrophe, and said to the destroying angel, “It is enough; now relax your hand.” And the angel of the Lord was standing by the threshing floor of Ornan the Jebusite.

Then David raised his eyes and saw the angel of the Lord standing between earth and heaven, with his drawn sword in his hand stretched out over Jerusalem. Then David and the elders, covered with sackcloth, fell on their faces.

And David said to God, “Is it not I who commanded to count the people? Indeed, I am the one who has sinned and acted very wickedly, but these sheep, what have they done? Lord, my God, just let Your hand be against me and my father’s household, and not against Your people as a plague.” David’s Altar

Then the angel of the Lord commanded Gad to say to David, that David was to go up and build an altar to the Lord on the threshing floor of Ornan the Jebusite.

So David went up at the word of Gad, which he spoke in the name of the Lord.