Thematic Bible: Natural rocks sometimes used as

Then Gideon went in and prepared a kid and unleavened cakes of an ephah of flour. The meat he put in a basket and the broth in a pot, and brought them to Him under the oak and presented them. And the Angel of God said to him, Take the meat and unleavened cakes and lay them on this rock and pour the broth over them. And he did so. Then the Angel of the Lord reached out the tip of the staff that was in His hand, and touched the meat and the unleavened cakes, and there flared up fire from the rock and consumed the meat and the unleavened cakes. Then the Angel of the Lord vanished from his sight.

So Manoah took the kid with the cereal offering and offered it upon a rock to the Lord, the Angel working wonders, while Manoah and his wife looked on. For when the flame went up toward the heavens from the altar, the Angel of the Lord ascended in the altar flame. And Manoah and his wife looked on, and they fell on their faces to the ground.