And therefore it is said, No man can say that Jesus is Lord, but by the Holy Ghost. And on one occasion, scarcely even the apostles themselves are deemed worthy to hear the words, You shall receive the power of the Holy Ghost coming upon you. For this reason, also, I think it follows that he who has committed a sin against the Son of man is deserving of forgiveness; because if he who is a participator of the word or reason of God cease to live agreeably to reason, he seems to have fallen into a state of ignorance or folly, and therefore to deserve forgiveness; whereas he who has been deemed worthy to have a portion of the Holy Spirit, and who has relapsed, is, by this very act and work, said to be guilty of blasphemy against the Holy Spirit. (Book I, Chapter 3, Part 7)

The Greek blasphemos originally meant to speak evil, slander, or do harm through speaking. It came to be understood as saying or doing what is harmful to God.

In the third chapter of Mark, Jesus is quoted as saying, "Truly I say to you, all sins shall be forgiven the sons of men, and whatever blasphemies they utter; but whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin." (New International Version)

The key to understanding the meaning of Jesus may be in his use of "guilty." The Greek is enochos meaning to be bound, under obligation, or subject to; in the original Greek it was most often used my someone held by, possessed with love and zeal for anything.

So we might hear Jesus saying, "Whoever speaks falsely regarding the holy spirit cannot be unbound, but through this eternal error is kept in bondage."

But the implication, at least for me, is bondage to the holy spirit.