I agree that in Rev 3:5 Jesus is not actually implying that these people were in the book of life in the first place but assuring them that if they accept him then they will be in it and not be blotted out of it because when you are saved you will never be unsaved. So if these Sardis people accept Jesus then that means they will be in the book of life and also in the Lamb’s book of life. I believe that the two are different books with different list of recording, but it then confuses me that for Sardis believers to be in the book of life through accepting Jesus and at the same time be in the Lamb’s book of life. Please help me understand the difference of these two books if there is any and also explain how come the Sardis people can be in both of the books, if that is the case anyway.
The Book of Life includes the name of everyone ever born, whether a believer or not (Psalm 139:16). The Lamb’s Book of Life only contains the names of those in the Church (Rev. 21:27). Names can be blotted out of the Book of Life, but if your name is written in the Lamb’s Book of Life it can’t be blotted out of either.
In His letter to the Church in Sardis the Lord said there were some who had not soiled their clothes (a symbol for unrighteousness) but would walk with Him dressed in white. The Lord said that he who overcomes will be like them, and He would never blot their names out of the Book of Life. No mention is made of the Lamb’s Book of Life.
In each of the seven letters overcomers are those who resist the tendency to either add to or subtract from the pure gospel, but rely entirely on the Lord’s completed work for their salvation.
I believe the church in Sardis represents the main line denominational churches of today. This in an indication that there will be at least a few from these churches who are saved. They will understand that it takes more than just being a member and will become born again on their own initiative.