1 Chronicles 21:18-20

New King James Version

¹⁸ Therefore, the ^(A)angel of the Lord commanded Gad to say to David that David should go and erect an altar to the Lord on the threshing floor of Ornan the Jebusite. ¹⁹ So David went up at the word of Gad, which he had spoken in the name of the Lord. ²⁰ Now Ornan turned and saw the angel; and his four sons who were with him hid themselves, but Ornan continued threshing wheat.