The core message of the Bible is about how mankind has forfeited immortality, which was originally supplied by God through the Tree of Life, and how mankind may once again overcome death and live perpetually. The pure message has been largely lost due to Christianity's syncretism with Greek philosophy. Related teaching:
The book of Revelation ties together themes found in several Old Testament prophets, particularly Isaiah, Ezekiel, Daniel, and Zechariah. The symbolism in Revelation cannot be understood correctly in a vacuum, but must be understood based on how the symbols were used by the prophets to portray events that occurred long ago. Revelation constantly drawns on the prophets, Jesus, and the teaching of the Apostles to paint an abstract portrait of the last days. It is filled with warnings and encouragement for Christians in the coming tribulation.
David wrote: "The heavens declare the glory of God; And the firmament shows His handiwork. Day unto day utters speech, And night unto night reveals knowledge. There is no speech nor language Where their voice is not heard" (Psalm 19:1-3). Paul quoted this passage to show that the Gentiles had already heard the Gospel by observing the constellations (Rom. 10:18). God laid out the history of Israel sequentially, in advance, using 12 pictures.