'Angel of the Lord' in the Bible

But the angel of the Lord said to Elijah the Tishbite, “Arise, go up to meet the messengers of the king of Samaria, and say to them, ‘Is it because there is no God in Israel that you are going to inquire of Baal-zebub, the god of Ekron?’

The angel of the Lord said to Elijah, “Go down with him; do not be afraid of him.” So he stood and went down with him to the king.

Then it came to pass that night, that the angel of the Lord went forth and struck down 185,000 [men] in the camp of the Assyrians; when the survivors got up early in the morning, behold, all [185,000] of them were dead.