Phil 4:3, Rev 3:5, Rev 20:12,15, Rev 21:27, Dan 12:1, Ex 32:32, Lk 10:20

In the Old Testament, it is written that all those whose names are written in the book of life in heaven will be saved. (Dan 12:1, Ex 32:32)

Dan 12:1 And at that time shall Michael stand up, the great prince which standeth for the children of thy people: and there shall be a time of trouble, such as never was since there was a nation even to that same time: and at that time thy people shall be delivered, every one that shall be found written in the book.

Ex 32:32 Yet now, if thou wilt forgive their sin--; and if not, blot me, I pray thee, out of thy book which thou hast written.

Those who believe in Jesus as the Christ have their names written in the book of life in heaven. (Luke 10:20, Philippians 4:3, Revelation 3:5)

Luke 10:20 Notwithstanding in this rejoice not, that the spirits are subject unto you; but rather rejoice, because your names are written in heaven.

Philippians 4:3 And I intreat thee also, true yokefellow, help those women which laboured with me in the gospel, with Clement also, and with other my fellowlabourers, whose names are in the book of life.

Revelation 3:5 He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels.

Only those whose names are written in the Lamb's book of life enter the kingdom of heaven. (Revelation 2:27)

Revelation 2:27 And he shall rule them with a rod of iron; as the vessels of a potter shall they be broken to shivers: even as I received of my Father.

Those who do not believe in Jesus as the Christ will not have their names written in the Lamb's book of life and will live as slaves to Satan and go to hell. (Rev 13:8, Rev 20;12,15)

Rev 13:8 And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.

Rev 20:12 And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works. 15 And whosoever was not found written in the book of life was cast into the lake of fire.