01 · A letter
Written to seven churches that already existed
Revelation is an apocalypse, a prophecy, and a letter. The letter part is not decoration. John writes to Ephesus, Smyrna, Pergamum, Thyatira, Sardis, Philadelphia, and Laodicea — congregations that could be faithful or compromised in the 60s, that could hold fast 'for a little while,' that could be kept from 'the hour of trial that is coming on the whole oikoumenē.'
A book about events twenty centuries later cannot keep a promise to Philadelphia or threaten to remove a lampstand from Ephesus. Whatever else the visions do, they must first mean something to the people named on the envelope.
What thou seest, write in a book and send it to the seven churches: unto Ephesus, and unto Smyrna, and unto Pergamum, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.