Fr. John Corbett, O.P., spoke at my parish this past Tuesday on the Book of Revelation, as part of a Lenten speaker series my Lay Dominican chapter is sponsoring.
Revelation, he said, is a pastoral letter written to address two difficulties faced by the Christians in Asia Minor. One difficulty was the persecution of Domitian. The other difficulty, perhaps more relevant to us today, is the problem of love grown cold.
The Seven Churches mentioned in Revelation were all founded at a time when the Gospel wasn't just Good News, it was current events. Great things had happened, wonderful promises had been made, mighty deeds had been worked.
And then... ten, twenty, sixty years passed.
When God has done great things for you, it's natural to ask, "What's next? What will God do today?" And what if the thing that God does next is... nothing?
You could probably use a letter of exhortation, too.
Which is what St. John provides, in apocalyptic style. According to Fr. Corbett, all apocalyptic writing is intended to answer the question, "Is God faithful to His promises?" The question isn't answered in a catechetical style (i.e., "Yes.") because it isn't being asked in a catechetical style. It's being asked in an uncomfortable, indirect, unsettled style -- which, come to think of it, may be why apocalyptic writing is itself uncomfortable, indirect, and unsettling.