'Angel of the Lord' in the Bible

And the man who was between the mountains, answering, said to the angel of the Lord, We have gone up and down through the earth, and all the earth is quiet and at rest.

Then the angel of the Lord, answering, said, O Lord of armies, how long will it be before you have mercy on Jerusalem and on the towns of Judah against which your wrath has been burning for seventy years?

And he let me see Joshua, the high priest, in his place before the angel of the Lord, and the Satan at his right hand ready to take up a cause against him.

And the angel of the Lord made a statement to Joshua, and said,

In that day the Lord will be a cover over the people of Jerusalem; and he who is feeble among them in that day will be as strong as David, and the family of David will be as God, as the angel of the Lord before them.