Alma 39: 5-6
Know ye not, my son, that these things are an bomination in the sight of the Lord; yea, most abominable above all sins save it be the shedding of innocent blood or denying the Holy Ghost?
For behold, if ye deny the Holy Ghost when it once has had place in you, and ye know that ye deny it, behold, this is a sin which is unpardonable; yea, and whosoever murdereth against the light and knowledge of God, it is not easy for him to obtain forgiveness; yea, I say unto you, my son, that it is not easy for him to obtain a forgiveness.

1. Denying the Holy Ghost KNOWINGLY is the unpardonable sin.
   
2. Murdering against the light and knowledge of God is forgivable, but not completely. "It is not easy for him to obtain a forgiveness." (As if to say "A level of forgiveness.)