What does the "book of life" in the Bible means?

Some people say everyone's name are written in the book of life and when you continue in sin, God erases your name from the book of life. In other words, Jesus died for everyone and placed their names in the book of life and it is now up to them to accept the offer of salvation and if they refuse their names will be erased from the book of life. Others also say that if you are born again, and fall into sin, you name will also be erased from the book of life. They use this argument to draw a line through the doctrine of "eternal security of believers," or otherwise stated, "perseverance of the saints." The error of these arguments is a wrong understanding of the term "the book of life" and a confusion of the book of life with the "Lamb's book of life." It is also based on an out of context use and wrong application of the text where these terms are used.

What then is the correct understanding of the "book of life" as used in the Old Testament and the New Testament?

There are two ways in which the Bible makes use of the term "book of life."

The first one is to refer to the book of eternal life. This can be seen mostly in the New Testament in Revelation and in a few other places.

Revelation 20:15 declares, “If anyone’s name was not found written in the book of life, he was thrown into the lake of fire.” Revelation 17:8 teaches both eternal security and election of believers. This Book of Life is also mentioned in Revelation 3:5; 20:12; and Philippians 4:3. The Book of Life, in this context, is the set of names of those who were chosen by God before the foundation of the world to be adopted as His children to live with Him forever in heaven (Eph. 1:4,5,11; Rom. 8:29-30). The same book is also called the Lamb’s Book of Life because it contains the names of those who have been redeemed by the blood of the Lamb who was slain before the foundation of the world (Rev. 13:8; 21:27).

How can you be sure your name is written in the Book of Life? Repent of your sin and trust completely in the person and work of Christ for all righteousness (Philippians 4:3; Revelation 3:5). The only proof of election is repentance and perseverance. Those who are not elected does not repent or falls away after a while. Those who do fall away, were never born again in the first place (1 John 2:9). The Bible actually teach that those who trust in Christ alone, will never be erased from the book of life (Revelation 3:5; Romans 8:37-39). No true believer should doubt his eternal security in Christ unless he continues to live in sin (John 10:28-30)

The second way is when it refers to the physical book of life. In other words, those who are physically alive at a specific time.

For example, Psalm 69:28 says, “Let them [David’s enemies] be blotted out of the book of the living.” This “book of the living” should not be confused with the Lamb’s Book of Life. David is referring to earthly, physical life, not eternal life in heaven. The same is true of the “book” mentioned in Exodus 32:32-33. In these passages God basically said if someone disobeys His laws, He will blot them out from the book of life (the book of the living), meaning they will die. We know there are many Old Testament laws which state if you disobey these laws, you must be put to death (Ex. 31:14; 35:2). Therefore, the verses in this particular context that speaks of being blotted out of the book of life (or living) do not refer to the book of eternal life. God will not break His own plan which He decided upon in eternity past before creation. Every person whose name is written in the book of life will be saved because God said so and His plans cannot be resisted or broken by man. Every person's name in the book of eternal life will be saved and will reach heaven because Jesus died for them as planned by God who chose them in eternity past.

Conclusion: We may, therefore, state that there are two books of life in the Bible with different applications. The one is the book of the living (life) and the other one is the book of eternal life. For your name to be blotted out of the book of the living means to physically die and it does not necessarily mean to be blotted out of the book of eternal life. The second one is the book of (eternal) life and the names in this book was written down by God in eternity past before creation when He chose and predestined the sheep who will belong to Him. He gave their names to Christ in eternity past when the trinity made a covenant that the Son would come to earth to redeem the elect. Those whose names are in the book of life can never be removed. God put them there and He promises through His sovereign grace that they will be saved.