2 Samuel 24:22-25
24:22 Araunah told David, “My lord the king may take whatever he wishes and offer it. Look! Here are oxen for burnt offerings, and threshing sledges and harnesses for wood.
24:23 I, the servant of my lord the king, give it all to the king!” Araunah also told the king, “May the Lord your God show you favor!”
24:24 But the king said to Araunah, “No, I insist on buying it from you! I will not offer to the Lord my God burnt sacrifices that cost me nothing.” So David bought the threshing floor and the oxen for fifty pieces of silver.
24:25 Then David built an altar for the Lord there and offered burnt sacrifices and peace offerings. And the Lord accepted prayers for the land, and the plague was removed from Israel.