WHO IS WRITTEN IN THE BOOK?
The Bible does not say categorically whose names are registered in the Book of Life. Certainly faithful Christians are written in, especially those who have sacrificed to share the Gospel with others—Paul referred to “Clement also, and the rest of my fellow workers, whose names are in the Book of Life” (Philippians 4:3). The faithful in Old Testament times were also included—Moses pleaded for his people after their idolatry with the golden calf, “Yet now, if You will forgive their sin—but if not, I pray, blot me out of Your book which You have written” (Exodus 32:32). Abraham is a representative of those may not know the name of Jesus but they know Him through the Holy Spirit—he is “the father of all those who believe, though they are uncircumcised, that righteousness might be imputed to them also” (Romans 4:11).
Many are in spiritual darkness, but under the influence of the Holy Spirit they “seek the Lord, in the hope that they might grope for Him and find Him” (Acts 17:27). God reveals himself to them through His creation: “His invisible attributes are clearly seen, being understood by the things that are made, even His eternal power and Godhead,” so that “the Gentiles, who do not have the law, by nature do the things in the Law…who show the work of the law written in their hearts” (Romans 2:14,15). No doubt these also are written in the Book of Life.
It appears that those who at one time or another have responded to the Holy Spirit have had their names (along with the historical context of their lives and their individual circumstances) written in the Book of Life. On the other hand, those who resist or refuse the promptings of the Spirit do not have their names written in. The beast of Revelation 13 is given authority “All... whose names have not been written in the Book of Life” (Revelation 13:7,8).
Furthermore, names that have been written can later be removed. At the end of Revelation there is a solemn warning: "If anyone shall take away from the words of the book of this prophecy, God shall take away his part from the book of Life” (Revelation 22:19). Jesus told the church of Sardis, “He that overcomes shall be clothed in white raiment, and I will not blot out his name from the Book of Life; but I will confess his name before my father and before his angels” (Revelation 3:5). This verse refers to the very scene recorded in Revelation 4-7, where the Book of Life is opened by the “Lamb as though it had been slain.” In this judgment the names of those who do not “overcome” are “blotted out” or removed.
To summarize, the investigative judgment of Revelation 4-7 is analogous to the “Day of Atonement” of the Old Testament sanctuary service. It is a time when all trace of sin will be "blotted out" (Acts 3:19) from the "records" of those who have continued to trust in the Lord. It is also a time when the names of those who have not held “the beginning of [their] confidence steadfast to the end” will be blotted out of the book of life. (Hebrews 3:6).
Some shudder at the thought of being judged, aware of and condemned by the sin they know exists in their own hearts. But we should always remember that it is God the Father, the One who “so loved the world that He gave His only begotten Son,” who is giving the Book of Life to Jesus. And Jesus, the “Lamb that was slain,” who gave his life for us, is the one who will open the scroll. God carries out a judgment because He wants us to be saved!
Daniel saw that the purpose of the judgment is to rescue those who love God (the “saints“) from this world of sin so they can live forever in His glorious kingdom: “The court was seated and the books were opened... Judgment was made in favor of the saints of the most High, and the time came for the saints to possess the kingdom…then the kingdom and dominion and the greatness of the kingdoms under the whole heaven shall be given to the people, the saints of the Most High. His kingdom is an everlasting kingdom” (Daniel 7:10, 22, 26,27). The investigative judgment is good news! Although the reign of sin seems endless and sometimes the pressures of this world seem overwhelming, Jesus promised that He is able to keep those who want to be kept by Him. “My sheep hear My voice, and I know them, and they follow Me. And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand. My Father, who has given them to Me is greater than all, and no one is able to snatch them out of My Father’s hand” (John 10:27-29).