The concept of “blasphemy against the Spirit” is mentioned in Mark 3:22–30 and Matthew 12:22–32
Matthew 12:31-32
King James Version
31 Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.
32 And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.
.
Jesus has just performed a miracle. A demon-possessed man was brought to Jesus, and the Lord cast the demon out, healing the man of blindness and muteness. The eyewitnesses to this exorcism began to wonder if Jesus was indeed the Messiah they had been waiting for. A group of Pharisees, hearing the talk of the Messiah, quickly quashed any budding faith in the crowd: “It is only by Beelzebul, the prince of demons, that this fellow drives out demons,” they said (Matthew 12:24).
Matthew 12:31-32
King James Version
31 Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.
32 And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.
.
Jesus has just performed a miracle. A demon-possessed man was brought to Jesus, and the Lord cast the demon out, healing the man of blindness and muteness. The eyewitnesses to this exorcism began to wonder if Jesus was indeed the Messiah they had been waiting for. A group of Pharisees, hearing the talk of the Messiah, quickly quashed any budding faith in the crowd: “It is only by Beelzebul, the prince of demons, that this fellow drives out demons,” they said (Matthew 12:24).