'Angel' in the Bible

But the angel of Jehovah said to Elijah the Tishbite, Arise, go up to meet the messengers of the king of Samaria, and say unto them, Is it because there is no God in Israel, that ye go to inquire of Baal-zebub, the god of Ekron?

And the angel of Jehovah said unto Elijah, Go down with him: be not afraid of him. And he arose, and went down with him unto the king.

And it came to pass that night, that the angel of Jehovah went forth, and smote in the camp of the Assyrians a hundred fourscore and five thousand: and when men arose early in the morning, behold, these were all dead bodies.