Revelation is a book of symbols – some of which are identified in scripture, and others are left for us to interpret. Here are the main points.
The context of Revelation 13:8 begins in verse 1, where the beast, having seven heads, ten horns with crowns, and the name of blasphemy on his heads, rises out of the sea. Verse 8, speaking of this beast, reads: “All the inhabitants of the earth will worship it – all those whose names have not been written in the book of life which belongs to the Lamb slain from the foundation of the world.”
We learn from Ephesians 1:4 that the Church is chosen in Jesus “before the foundation of the world.” This shows that God had planned there to be a class of people who would become the “body of Christ”(1 Corinthians 12:27). These are the ones whose names are written in the book of life. These are God’s “called out” ones, the “people for His name” (Acts 15:14), the “Little Flock” (Luke 12:32).
So it is that everyone who is not part of this “Little Flock” – the vast majority of mankind – will worship the beast. In the Scriptures, beasts represent governments (see Daniel 8:20,21). This beast with seven heads represents an empire, and the horns with crowns represent their rulers. We can see in history that there has been an empire which has been identified with the number seven. This is Rome (known as the city of seven hills).
This beast, or empire, was a church-state system. The Catholic church crowned the kings. During the dark ages, the “civilized world” worshipped the Papacy (symbolized as the dragon giving power to the beast – Revelation 13:4). Any in opposition would have faced torture and death. There were thousands of Christian martyrs.
But what happens to those who are not found in the book of life? These are resurrected on earth (John 5:28,29; Matthew 6:10) during Christ’s 1,000 year reign (Revelation 20:4). Mankind will then learn righteousness through the blessed reign of Jesus and His Bride. “And the Spirit and the bride say, Come. And let him that hearth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely…on either side of the river was there the tree of life…and the leaves of the tree were for the healing of the nations.” (Revelation 22:17, 2)