The term blasphemy may be generally defined as “defiant irreverence.” The term can be applied to such sins as cursing God or willfully degrading things relating to God. Blasphemy is also attributing some evil to God or denying Him some good that we should attribute to Him. This particular case of blasphemy, however, is called “the blasphemy against the Holy Spirit” in Matthew 12:31. The Pharisees, having witnessed irrefutable proof that Jesus was working miracles in the power of the Holy Spirit, claimed instead that the Lord was possessed by a demon (Matthew 12:24). Notice in Mark 3:30 Jesus is very specific about what the Pharisees did to commit
blasphemy against the Holy Spirit: “He said this because they were saying, ‘He has an impure spirit.’”