William Burkitt on Luke 12:10

Although never man preached or lived as Christ did, yet there were those that spoke against him; the person of Jesus was contemned and reproached, for the meanness of his birth, for the poverty of his condition, for the freedom of his conversation; but this sin did not exclude the hope of pardon: Whosoever shall speak a word against the Son of man, it shall be forgiven him; that is, whoever affirms that divine power by which I do my miracles, to be the power of the devil, such blasphemy will be unpardonable, because it is to resist the last remedy, and to oppose the best means of men's conviction; for what could be done more to convince men that Christ was the true and promised Messiah, than to work so many miracles before their eyes to that purpose. Now these miracles, though evidently wrought by the power of God, the Pharisees ascribed to the power of the devil, which our Saviour calls Blasphemy against the Holy Ghost, and a sin unpardonable.