In Revelation chapter three, verses four through six, Jesus continues his admonition to the Church in Sardis. He says,
"Yet you have a few people in Sardis who have not soiled their clothes. They will walk with me, dressed in white, for they are worthy. 5 The one who is victorious will, like them, be dressed in white. I will never blot out the name of that person from the book of life, but will acknowledge that name before my Father and his angels. 6 Whoever has ears, let them hear what the Spirit says to the churches."
This passage is pretty clear cut; here Jesus acknowledges that some members of the church at Sardis are still in good standing; he uses the metaphor of wearing white clothing to signify the remaining purity of their souls. He is telling the congregation that their deeds matter and to cling to his teachings and remain repentant until the day of his second coming so that their name will remain in the book of life.
The wikipedia entry on the Book of Life lists information about the book of life in the Old and New Testament, as well as in the Apocrypha and notes that scripture says that when someone's name has been found to have been blotted out of the Book of Life on Judgement Day, they are thrown in to the Lake of Fire. These specific verses are Revelation 20, verses 12 and 15. I find wikipedia to be a great resource because of the sources listed at the end of each article; even though it's not considered acceptable to use wikipedia for academic work because it is editable, it is a great wellspring of information for original sources and documentation.
If you want to accept Salvation from Christ here are some resources:
A Prayer for Salvation from Christ:
Lord
Jesus, I confess my sins and ask for your forgiveness. Please come into
my heart as my Lord and Savior. Take complete control of my life and
help me to walk in Your footsteps daily by the power of the Holy Spirit.
Thank you Lord for saving me and for answering my prayer.
A more detailed step by step process:
https://www.wikihow.com/Accept-Jesus-Into-Your-Life
