It is worth noting that the author of the Apocalypse exercised an authority over the Asian churches that went beyond that normally associated with NT prophets. This leads to the conclusion that although he wrote as a prophet, he functioned among his churches as an apostle.1
He commends the Church of Ephesus for trying and convicting “them which say they are apostles, and are not,” by which he implies his own undoubted claim to apostolic inspiration (Rev. 2:2+), as declaring in the seven epistles Christ’s will revealed through him.2
1 Robert H. Mounce, The Book of Revelation (Grand Rapids, MI: William B. Eerdmans Publishing Co., 1977), 26.
2 A. R. Fausset, “The Revelation of St. John the Divine,” in Robert Jamieson, A. R. Fausset, and David Brown, A Commentary, Critical and Explanatory, on the Old and New Testaments (Oak Harbor, WA: Logos Research Systems, Inc., 1997, 1877), Rev. 1:1.