'Angel' in the Bible

And the angel of Jehovah 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 not a God in Israel, that ye go to inquire of Baal-zebub the god of Ekron?

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

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