What is a "sin against the Holy Spirit"?
This expression is taken from the Gospel, as we read in Mt 12, 32:
“All sin and blasphemy shall be forgiven unto men, but blasphemy against the Holy Spirit shall not be forgiven. And whosoever shall speak a word against the Son of man, it shall be forgiven him: but whosoever shall speak a word against the Holy Ghost, it shall not be forgiven him in this world, neither in the world to come."
Christ pronounced these words after the Pharisees tried to discredit his miracles, saying that he worked them by the power of Beelzebul, Prince of demons (Mt 12:2-4).
These sins imply the refusal to accept the salvation that God offers to man through the Holy Spirit, or the radical refusal to accept God’s forgiveness. It is the sin that is committed by the person who claims to have a “right” to persist in evil. They include:
1. Desperation, which makes us distrust God's mercy or encourages us to sin more. It generates the presumption of being saved without merits or effort; and it excludes the fear of divine justice.
2. What makes us enemies of the divine gifts that lead us to conversion: the rejection or opposition to Catholic truths known as such (which leads us to contradict the truth in order to sin with peace of mind), and envy or hatred of grace (envy of grace given to others, or sadness for the action of grace in others, and for the growth of God's grace in the world).
3. And finally, what prevents us from leaving sin: final impenitence (the refusal to repent and leave our sins), and obstinacy in sin (the insistence on the resolve to continue sinning).
Evidently this sin is not reached suddenly, but after having been living in sin for long. The malice of this sin implies many other sins that keep on destroying man until he rejects conversion. Thus, Our Lord says that this sin will not be forgiven either in this world or in the next (Mt 12:32). This does not mean that this sin "cannot" be forgiven by God, but that it does not in itself give any opening for forgiveness (it cuts off all avenues for repentance and return to God). However, nothing can close the divine omnipotence and mercy, which can cause the conversion of the most hardened heart just as it can miraculously cure a deadly disease.
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