'Angel of God' in the Bible

And thy bondmaid said, Let the word of my lord the king now be comfortable; for as an angel of God, so is my lord the king to discern good and bad; and Jehovah thy God will be with thee.

in order to turn the appearance of the thing has thy servant Joab done this thing; but my lord is wise, according to the wisdom of an angel of God, to know all that is in the earth.

And he has slandered thy servant to my lord the king; but my lord the king is as an angel of God; do therefore what is good in thy sight.