When Jesus spoke to His disciples, He said that they should rejoice that there names were written in heaven.
…rejoice because your names are written in heaven.” Luke 10:20
When we examine the original Greek language in which this verse was written, the verb that is used for “written,” carries with it the idea that these names were written in heaven from eternity. In other words, because God knows all things, He has always been aware of every person who would choose to follow Jesus and rely upon Him for their Salvation. These individuals have always been known to God and there names would remain in the book of life—forever.
There is also an indication that the “Book of Life,” contains that names of every person who will be born upon the earth. Their names will remain in this book, until the last day of their life. Upon their death, if they have rejected the command of God to believe upon Jesus for their Salvation, then and only then, will their name be blotted out of The Book of Life.”