The Purpose of the Book of Revelation

All Scripture, including Revelation, has practical value for exhortation, comfort, and training in righteousness.  Paul underlines this point in 2 Tim 4:1-5 by drawing a contrast between solid teaching of the gospel and people's desire to have teachers who "say what their itching ears want to hear" (4:3)".  God gave us Revelation not to tickle our fancy, but to strengthen our hearts.  Vern Poythress, The Returning of the King, p. 11