Revelation 22:18–19 works out the consequences of adding or subtracting from the words of the prophecy of Revelation. Revelation 22:20a repeats that the Dispenser of these consequences is in fact coming soon and so puts pressure on the readers to respond properly (see Revelation 22:7, Revelation 22:12). Revelation 22:20b gives us John’s response to the promise of Revelation 22:20a—and so invites the readers to respond similarly. In Revelation 22:21 John adds the customary epistolary closing pronouncement.
18 I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues described in this book,