'Altar to the Lord' in the Bible

Then the angel of the LORD commanded Gad to tell David that David should go up, and raise an altar to the LORD in the threshing floor of Ornan the Jebusite.

Then David said to Ornan, "Give me the place of this threshing floor, that I may build thereon an altar to the LORD. You shall sell it to me for the full price, that the plague may be stopped from afflicting the people."

David built an altar to the LORD there, and offered burnt offerings and peace offerings, and called on the LORD; and he answered him from the sky by fire on the altar of burnt offering.