. . . an open door to heaven.  Late in his life, the apostle John found himself on Patmos, a desert island on the Aegean Sea that served as a Roman penal colony.   The emperor Domitian had exiled him there as punishment for his continued preaching about Jesus.   It may have been a dismal setting, but John made the most of it.   He took the opportunity of this time of quiet to compose the Book of Revelation. In Scripture’s reading (Revelation...