1 Kings 19:18. It was so, when Elijah heard it, that he wrapped his face in his mantle, and went out, and stood in the entering in of the cave.
Covering the face was a sign of reverence in the presence of God. Thus Moses, when the Lord appeared to him in the burning bush, “hid his face, for he was afraid to look upon God” (Ex. 3:6). So the seraphim seen by Isaiah in his temple-vision covered their faces with two of their wings (Isa. 6:2).