'Angel of the Lord' in the Bible

But an angel of the Lord opened the doors of the prison by night, and brought them out, and said:

And when forty years were completed, there appeared to him, in the wilderness of Mount Sinai, an angel of the Lord in a flame of fire in a bush.

And an angel of the Lord spoke to Philip, saying: Arise, and go toward the south, to the road that leads from Jerusalem to Gaza; this is desert.

And behold, an angel of the Lord stood by him, and a light shone in the prison. And he gently struck Peter on the side, and awoke him, saying: Arise quickly; and his chains fell from his hands.

And immediately an angel of the Lord smote him, because he did not give God the glory. And having been eaten by worms, he expired.