Bede the Venerable

(ubi sup.) But John is called an angel not by community of nature, according to the heresy of Origena, but by the dignity of his office; for angel in Greek is in Latin, nuntius, (messenger,) by which name that man is rightly called, who was sent by God, that he might bear witness of the light, and announce to the world the Lord, coming in the flesh: since it is evident that all who are priests may by their office of preaching the Gospel be called angels, as the prophet Malachi says, The lips of the priest keep knowledge, and they seek the law at his mouth, because he is the Angel of the Lord of hosts. (Mal. 2:7)