ANGEL (Metaphorically)
The term angel is used metaphorically of a mystical representative. When Peter was released from prison and knocked on the door, those who had been praying for his release said, “He will be an angel” (Acts 12:15).
They assumed that Pedro was still in prison, and that the person at the door was his representative, his personified spirit, perhaps with very vague ideas of what they really meant.
In the book of Revelation (Rev. 2, 3) the letters to the seven churches are addressed to the angels of each of them. It means the spirit and character of the church personified in its mystical representative, each of them differing from the others, based on the state of the church represented.
The messages, although addressed to the literal churches then existing, also set forth the state of the church in its various phases from apostolic times to its rejection as a witness of Christ at the end of the Church age.