What the Bible says about Blasphemy against Holy Spirit
(From Forerunner Commentary)
Blasphemy against the Holy Spirit is the denial by the witness of his life that an individual was forgiven, received God's Holy Spirit, and then failed to live by faith, returning to a life of sin.
John W. Ritenbaugh
Living By Faith and God's Grace
A person who blasphemes the Holy Spirit allows Satan to influence him so thoroughly that he refuses to submit to God. He rejects the power of God‚s Spirit and defiantly shakes his fist at His Creator. In this state he is too proud and rebellious to repent, and thus God cannot forgive him.
Martin G. Collins
Are Some Sins Worse Than Others?