This Bible contradiction is from the Skeptic's Annotated Bible.
Matthew 12:31-32 View context
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.
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.
Mark 3:29 View context
But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation:
Luke 12:10 View context
And 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.
Acts 13:39 View context
And by him all that believe are justified from all things, from which ye could not be justified by the law of Moses.