It appears that different Bible writers used the expression ‘book of life’ in different ways. In Old Testament times it may have meant simply the register of all living people. It seems also to have had a special meaning as referring to the register of all who claimed to be God’s people (Exod 32:32-33; Ps 69:28). Among those known as God’s people, from Old Testament times to the present, there are those who become apostates or who were not genuine believers in the first place. They demonstrate this by openly and deliberately rejecting God, and God removes their names from the book of life. True believers do not reject God, and God does not remove their names from the book of life. They are assured of eternal life in its fulness (Exod 32:32-33; Rev 3:5; 21:22-25; see APOSTACY; BACKSLIDING). From this usage, ‘book of life’ has developed a more specific meaning. It becomes the register of all true believers – those whom God has chosen and who have received cleansing from sin through the blood of Jesus. Thus it becomes specifically the ‘Lamb’s book of life’ (Luke 10:20; Phil 4:3; Rev 13:8; 21:27). In the coming judgment, all whose names are not written in the Lamb’s book of life will suffer eternal punishment (Rev 17:8; 20:12-15).