6. “ I will not blot out his name out of the book of life"-- 3:5. This book of life is an allusion to a registry for worthy citizens, but the names of the deceased citizens are erased. This meant exclusion. But there were a few names in Sardis that would not be blotted out of the book of life. It clearly indicates that the names of the unworthy would be blotted out; but a name cannot be blotted out of the book of life, if it had never been recorded in it; so here is positive proof for the possibility of apostasy.