And to the angel of the church of Smyrna, write: The first and the last says these things, etc. He advises that the should write to the angel of Smyrna, that is, to the bishop; for that passage in the Acts of the Apostles testifies that a bishop is called an angel, where Peter comes and knocks on the door of the apostles, and it is said, "It is not Peter, but his angel."[FN22]
[FN22: Acts 9.15, Interestingly, Tyconius used this passage in Acts to prove that "angel" in Acts 9.15 meant Peter's own "spirit," and that John used the word "angel," not for the bishop of the church addressed in the letters in Rv 2 and 3, but as a metonymy for the Church itself. See Tyconius, Exposition of the Apocalypse, on Rv 1.19-20. CCSL 107A: 110, FC 134: 36.
Cassiodorus (footnote is translator's) in Fathers of the Church, Vol. 144, Cassiodorus, St. Gregory the Great, and Anonymous Greek Scholia, Writings on the Apocalypse, Chapter 2, section 5. [8], p. 19, Francis X. Gumerlock, Trans.