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.” The Book of Life is the set of names of  those who will live with God forever in heaven. It is the roll of those who are  saved. This Book of Life is also mentioned in Revelation  3:5; 20:12;  and Philippians  4:3. 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 Lord  Jesus (Revelation  13:8; 21:27).

How can you be sure your name is written  in the Book of Life? Be sure you’re saved. Repent of sin and believe in the Lord  Jesus Christ as your Savior (Philippians  4:3; Revelation  3:5). Once your name is written in the Book of Life, it is never erased (Revelation 3:5; Romans 8:37-39). No true  believer should doubt his eternal security in Christ (John 10:28-30).

The Great White Throne Judgment described in Revelation 20:11-15 is a judgment for unbelievers. That  passage makes it clear that no one at that judgment has his name in the Book of  Life (Revelation 20:12-14). Since their names are not in the  Book of Life, their fate is sealed, their punishment is sure.

Some  people point to Revelation  3:5 as “proof” that a person can lose his salvation. However, the promise of  Revelation  3:5 is clearly that the Lord will not erase a name: “He who overcomes . . .  I will not blot out his name from the Book of Life.” An overcomer is one who is  victorious over the temptations, trials, and evils of this world—in other words,  one who is redeemed. The saved are written in God’s registry and have the  promise of eternal security.

Another passage over which confusion  sometimes arises is Psalm 69:28:  “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.

God keeps good records. He knows His own, and He has set  the names of His children permanently in His book.