Answer:
While it sounds like this may be the meaning and prove predestination, it is really not what it is referring to at all.
It is in reference to the work that was done for their salvation before the foundation of the world. If you compare your verse with this one from earlier in Revelation it will help to clear this up….
Revelation 13:8 And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.
As an analogy, it is like if I in June purchased a ticket for everyone in my family to go to Hawaii at Christmas time. Then, at the airport one of my family members did not show up and I said, “Where is so and so, whose name was on a ticket since June”
Jesus desired EVERYONE to go to Heaven and purchased our tickets before the world was even formed with His own blood. That is, He had already made provision even before He created us.
I can’t imagine any of my family members passing up a free trip to Hawaii…but even worse is that so many will pass up a trip to paradise for all of eternity.