Heidegger's Bible Handbook: Revelation: Form of the Book

9. The form or method is Epistolary. Dramas are properly to be distinguished from the Prophecies.

The form or method of the book is generally ἐπιστολικὴ or Epistolary. Indeed, it has the ἐπιγραφὴν/ inscription and ὑπογραφὴν/ subscript of Epistles, with the name of the writer and of the Churches to which it was inscribed; and it is closed with an Apostolic blessing. All the transactions of the first vision are also Epistolary. But the remaining vision after Revelation 4 have a dramatic form, so that the entire Apocalypse is with good reason marked as a Prophetic drama. Now, the Dramas are to be properly distinguished from the Prophecies. The former are both preparations and, as it were, certain rehearsals and apparatuses of the visions, Revelation 1:9-20; 4; 5; 8:1-6; 15: and the choruses of the twenty-four Elders, four living creatures, Angels, etc., their hymns, prayers, and ἐπινίκια/victory-songs. But the predictions and types whereby future events are represented exhibit the Prophecies. In addition, all the visions, with the first two excepted, have about three acts, the Tragic calamities of the Church, and its liberation and ἐπινίκιον/victory-song or δοξολογίαν/ doxology.

Dr. Dilday's Lecture: "Revelation, Part 3"