What does 2 Kings 1:13 mean?

Elijah answered to the captain of fifty, “If I am a man of God, then let fire come down from the sky, and consume you and your fifty!” Then fire came down from the sky, and consumed him and his fifty.

Again he sent to him another captain of fifty with his fifty. He answered him, “Man of God, the king has said, ‘Come down quickly!’”

Elijah answered them, “If I am a man of God, then let fire come down from the sky, and consume you and your fifty!” Then God’s fire came down from the sky, and consumed him and his fifty.

Behold, fire came down from the sky, and consumed the last two captains of fifty with their fifties. But now let my life be precious in your sight.”

Yahweh’s angel said to Elijah, “Go down with him. Don’t be afraid of him.” Then he arose, and went down with him to the king.

He said to him, “Yahweh says, ‘Because you have sent messengers to inquire of Baal Zebub, the god of Ekron, is it because there is no God in Israel to inquire of his word? Therefore you will not come down from the bed where you have gone up, but you will surely die.’”