This is something I've wondered about for a long time. I've asked people but could never really get a straight answer that explains it in a way I can understand. What is the unforgivable sin? Matthew 13:31-32 What is considered blasphemy against the Holy Spirit? What is it that classifies as "speaking against the Holy Spirit"? I'd love to hear some input from other members here on this. Please guys, this is NOT a "God exists vs there is no God thread". If you do not believe and you know the bible well enough to give your input, please do. But let's not make this about anything other than the OP.