The term “book of life” had appeared earlier in Revelation 3:5. Various places in the Old Testament make reference to a register containing the names of all those through the ages who would inherit eternal life (Exodus 32:32; Psalm 69:28; Isaiah 4:3; Daniel 12:1; Malachi 3:16). The New Testament also makes mention of such a list (Luke 10:20; Philippians 4:3; Hebrews 12:23). In the present passage the Lamb himself possesses this book (John 17:2). Its content determines who enters the New Jerusalem, from any tribe or race or social standing.
27 But nothing unclean will ever enter it, nor anyone who does what is detestable or false, but only those who are written in the Lamb’s book of life.