Blasphemy against the Holy Spirit is uniquely grave in the stated context.

³¹Wherefore 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.

³²And 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.

²⁸Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme:

²⁹But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation:

³⁰Because they said, He hath an unclean spirit.

¹⁰And whosoever shall speak a word against the Son of man, it shall be forgiven him: but unto him that blasphemeth against the Holy Ghost it shall not be forgiven.