Jesus teaches that blasphemy against the Holy Spirit is a sin that is unforgivable. The “unforgivable” aspect to this can be alarming and troubling. Undoubtedly, there’s no Christian that would want to be guilty of blasphemy against the Holy Spirit!
Matthew 12:31: Therefore I tell you, every sin and blasphemy will be forgiven people, but the blasphemy against the Spirit will not be forgiven.
First, just understanding the word “blasphemy” will help. Merriam-Webster defines the English word as, “the act of insulting or showing contempt or lack of reverence for God.” In Greek, it can mean “vilification” or “evil speaking” or “railing against”. However, pinning down the exact meaning and sense in which Jesus is speaking requires us to consider this passage more closely.