'Angel of the Lord' in the Bible

But [as] he was considering these things, behold, an angel of the Lord appeared to him in a dream, saying, "Joseph, son of David, do not be afraid to take Mary [as] your wife, for what has been conceived in her is from the Holy Spirit.

And Joseph, [when he] woke up from sleep, did as the angel of the Lord commanded him, and he took his wife

Now [after] they had gone away, behold, an angel of the Lord appeared in a dream to Joseph, saying, "Get up, take the child and his mother and flee to Egypt, and stay there until I tell you. For Herod is about to seek the child to destroy him."

Now [after] Herod had died, behold, an angel of the Lord appeared in a dream to Joseph in Egypt,

And behold, there was a great earthquake, for an angel of the Lord descended from heaven and came up [and] rolled away the stone and sat down on it.