So they are Christians which I would surmise you mean saved. But have fallen into error which again I would surmise you mean they are at risk of loosing their salvation? If that is true were they elect and saved or were they not elect and just going through the motions? That’s not a gotcha question. It’s a legitimate observation of the duplicity of statements as I see it.
If they are one of the elect they are “once saved always saved”. Yet those who hold to the concept of predestination would renounce those who hold to once saved always saved.
In Revelation we are cautioned about being blotted out of 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.
Revelation 22:19 - And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and [from] the things which are written in this book.
Psalm 69:28 Let them be blotted out of the book of the living, and not be written with the righteous.
Exodus 32:33 But the LORD said to Moses, “Whoever has sinned against me, I will blot out of my book.
How can we be blotted out of the “book of life” if we weren’t once in it?
We also know that there are those who’s names were not written in the Lambs Book of Life.
And they that dwell on the earth shall wonder, whose names were not written in the book of life from the foundation of the world. (Revelation 17:8)
So it can’t be that all people are written in the Lambs book of life but if they die without turning to Jesus are taken out of the Lambs book of life. It’s only those who believe that are written in the lambs book of life.
Were those people who were once in the “book of life” predestined for a period of time but later not? Where they predestined and “written in the book of life” but later un-predestined and “blotted out” of the book of life?
2 Corinthians 4:8-9 We are troubled on every side, yet not distressed; we are perplexed, but not in despair;
9.Persecuted, but not forsaken; cast down, but not destroyed;