Many have noted the simplicity of the title given by the author as simply John. This in itself is evidence for the apostleship of the author:
The writer avouches himself as John; but, though there may have been other men named John in the Church at this time, John the Presbyter and others, still it is well-nigh impossible to conceive any other but John the Apostle who would have named himself by this name alone, with no further style or addition. We instinctively feel that for any one [sic] else there would have been an affectation of simplicity, concealing a most real arrogance, in the very plainness of this title. Who else, without this arrogance, could have assumed that thus to mention himself was sufficient to ensure his recognition, or that he had a right to appropriate this name in so absolute a manner to himself?1The writer is evidently known to the readers and needs no specific introduction. Isa. 6:1; Jer. Jer. 1:1). His identity and authority are known to readers to whom he needs no introduction.2 Beale notes that the form of identification, lacking any specific claim to apostleship, also renders the use of John as a pseudonym by some other writer unlikely: If an unknown author were attempting to identify himself with a well-known Christian figure like the apostle John, he would probably call himself not just John but John the apostle. 3 Hilgenfield concurs: An unknown John, remarks Hilgenfield, whose name has disappeared from history, leaving hardly any trace behind it, can scarcely have given commands in the name of Christ and the Spirit to the seven churches. 4
1 Richard Chenevix Trench, Commentary on the Epistles to the Seven Churches in Asia (Eugene, OR: Wipf and Stock Publishers, 1861), 2-3.
2 Colin J. Hemer, The Letters to the Seven Churches of Asia in Their Local Setting (Grand Rapids, MI: William B. Eerdmans Publishing Company, 1989), 30-31.
3 Gregory K. Beale, The Book of Revelation: A Commentary on the Greek Text (Grand Rapids, MI: William B. Eerdmans Publishing Co., 1999), 34.