John Gill

And it was so, when Elijah heard it, that he wrapped his face in his mantle,.... Through reverence of the divine Majesty he perceived was there, and through shame and confusion under a sense of his impurity, imperfections, and unworthiness, as the seraphim in Isa 6:2, and as Moses, Exo 3:6, and went out and stood in the entering in of the cave; he attempted to come forth out of the cave upon the divine order, Kg1 19:11, but was stopped by the terrible appearances of the wind, earthquake, and fire, a little within it; but now he came quite out, and stood at the mouth of it, to hear what the Lord would say unto him: and, behold, there came a voice unto him, and said, what dost thou here, Elijah? the same question is here put as in Kg1 19:9, though there by an angel, here by the Lord himself.