This phrase is used seven times in the NT, all but one (Phil 4:3) in the book of Revelation. Unlike in this verse, four of the uses are anarthrous (do not use definite articles). The only example in the OT is Ps 69:28. The book of life clearly records the names of individuals, and every individual ever to live is evaluated as to inclusion in the book. It appears that names may be erased from the book (Rev 3:5; Ps 69:28), yet some are not included in the book “from the foundation of the world.” In this verse, the book of life is identified as belonging to the “Lamb that was slain.” This verse and Rev 20:15; 21:27 indicate that the list is of those who are saved. It is difficult to put these details together, but it may be that the names are established in the book from before the foundation of the world, but in the course of each person’s life, there may come a time when it becomes evident that they are not in the book, which is tantamount to being erased. Could it be that from God’s perspective, He began with all names in the book and then erased certain ones, before the foundation of the world? And from a temporal perspective, the absence of one’s name in the book (erasure) is at some point demonstrated.
Matthew 1 (WEB)
1The book of the genealogy of Jesus Christ, the son of David, the son of Abraham.
2Abraham became the father of Isaac. Isaac became the father of Jacob. Jacob became the father of Judah and his brothers. 3Judah became the father of Perez and Zerah by Tamar. Perez became the father of Hezron. Hezron became the father of Ram. 4Ram became the father of Amminadab. Amminadab became the father of Nahshon. Nahshon became the father of Salmon. 5Salmon became the father of Boaz by Rahab. Boaz became the father of Obed by Ruth. Obed became the father of Jesse. 6Jesse became the father of King David. David the king became the father of Solomon by her who had been Uriah’s wife. 7Solomon became the father of Rehoboam. Rehoboam became the father of Abijah. Abijah became the father of Asa. 8Asa became the father of Jehoshaphat. Jehoshaphat became the father of Joram. Joram became the father of Uzziah. 9Uzziah became the father of Jotham. Jotham became the father of Ahaz. Ahaz became the father of Hezekiah. 10Hezekiah became the father of Manasseh. Manasseh became the father of Amon. Amon became the father of Josiah. 11Josiah became the father of Jechoniah and his brothers at the time of the exile to Babylon.
12After the exile to Babylon, Jechoniah became the father of Shealtiel. Shealtiel became the father of Zerubbabel. 13Zerubbabel became the father of Abiud. Abiud became the father of Eliakim. Eliakim became the father of Azor. 14Azor became the father of Zadok. Zadok became the father of Achim. Achim became the father of Eliud. 15Eliud became the father of Eleazar. Eleazar became the father of Matthan. Matthan became the father of Jacob. 16Jacob became the father of Joseph, the husband of Mary, from whom was born Jesus, who is called Christ.
17So all the generations from Abraham to David are fourteen generations; from David to the exile to Babylon fourteen generations; and from the carrying away to Babylon to the Christ, fourteen generations.
18Now the birth of Jesus Christ was like this: After his mother, Mary, was engaged to Joseph, before they came together, she was found pregnant by the Holy Spirit. 19Joseph, her husband, being a righteous man, and not willing to make her a public example, intended to put her away secretly. 20But when he thought about these things, behold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, don’t be afraid to take to yourself Mary as your wife, for that which is conceived in her is of the Holy Spirit. 21She shall give birth to a son. You shall name him Jesus, for it is he who shall save his people from their sins.”
22Now all this has happened that it might be fulfilled which was spoken by the Lord through the prophet, saying,
23“Behold, the virgin shall be with child,
and shall give birth to a son.
They shall call his name Immanuel,”
which is, being interpreted, “God with us.”
24Joseph arose from his sleep, and did as the angel of the Lord commanded him, and took his wife to himself; 25and didn’t know her sexually until she had given birth to her firstborn son. He named him Jesus.