By Clement Harrold
July 2, 2026
One of the more disconcerting moments in the Gospels comes when Jesus informs His critics that there is one particular kind of sin that will not be forgiven.
For context, Jesus has just healed a blind and mute demoniac when the Pharisees begin to murmur that He is only able to cast out demons by the power of Beelzebul (another name for Satan).
In response to this slanderous accusation, Jesus emphatically affirms that “it is by the Spirit of God that I cast out demons” (Matt 12:28).
The exchange that follows is recorded in Matthew, Mark, and Luke:
“Therefore I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven. And whoever says a word against the Son of man will be forgiven; but whoever speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.” (Matt 12:31–32)
“Truly, I say to you, all sins will 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” — for they had said, “He has an unclean spirit.” (Mark 3:28–30)
“And every one who speaks a word against the Son of man will be forgiven; but he who blasphemes against the Holy Spirit will not be forgiven.” (Luke 12:10)
What are we to make of this perplexing warning? And does the unforgivable sin mean there is a limit on God’s mercy?
Three Interpretations
In his Summa Theologiae, St. Thomas Aquinas explains that there are at least three different ways of understanding the unforgivable sin against the Holy Spirit.
First Interpretation: Blasphemy
The first interpretation is that “a sin against the Holy Spirit occurs when... something blasphemous is said against the Holy Spirit” (ST II-II.14.1).
Whereas Christ cast out demons by the power of the Holy Spirit, the Pharisees attributed His exorcisms to Satan. By characterizing the works of the Holy Spirit as diabolical, the Pharisees therefore committed a grave sin of blasphemy.
Second Interpretation: Refusal to Repent
The second interpretation is that the sin against the Holy Spirit is specifically the sin of “final impenitence.”
Since the Holy Spirit is the one who effects God’s forgiveness in our souls, blaspheming against the Holy Spirit means cutting ourselves off from the lifeline of grace. In this respect, the sinner who rejects the Holy Spirit as something diabolical is akin to a dying man rejecting his medicine as something poisonous.
Here Aquinas observes that Jesus never actually states that His opponents are guilty of the unforgivable sin. He simply warns them that this is a real future possibility should they continue to close themselves off from the Spirit.
Third Interpretation: Sins of Malice
The third interpretation is that the sin against the Holy Spirit occurs when someone sins out of fixed malice.
Here Aquinas unfolds the traditional distinction between sins of weakness, sins of ignorance, and sins of malice. According to one tradition, sins of weakness are a particular offense against the Father, sins of ignorance are a particular offense against the Son, and sins of malice are a particular offense against the Holy Spirit.
Sins of malice arise when someone “knowingly wills a bad spiritual thing, which is evil absolutely speaking and by which he is deprived of some spiritual good, in order to enjoy a temporal good” (ST I-II.78.1).
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Final Impenitence and the Role of the Spirit
Of the three foregoing interpretations, the second seems to be the most helpful and the most promising.
As the Gospel of John makes clear, it is the specific mission of the Holy Spirit both to convince the world of its sin (see John 16:8) and to bring about the forgiveness of sin (see John 20:22–23). Given this reality, it follows that blasphemy against the Holy Spirit is the sin of consciously vilifying and therefore rejecting the saving mercy of God.
The reason this sin is unforgivable is because the decision to turn one’s back on the Holy Spirit is by its very nature the decision to refuse to accept God’s forgiveness, or even to acknowledge the need for it.
Aquinas explains it this way:
For just as a disease is called incurable by the nature of the disease, because it destroys that by which a disease can be cured—for instance, because the disease destroys the power of the nature or because it induces a loathing of food and drink—even though God can cure even this sort of disease, so, too, a sin against the Holy Spirit is unforgivable by its nature insofar as it excludes the things through which the forgiveness of sin is effected. Yet a way of forgiving and healing is not thereby closed off to God’s omnipotence and mercy, through which such individuals are sometimes spiritually healed by a miracle, as it were. (ST I-II.78.3)
This last sentence reminds us that there is still hope even for a person who is currently choosing to reject the Holy Spirit. Through His omnipotence, God may yet soften the heart of that person to bring them to a place where they seek forgiveness for their sin before it is too late.
In his encyclical on the Holy Spirit, Dominum et Vivificantem, Pope St. John Paul II offers an additional reflection on why blasphemy against the Spirit prevents us from receiving His forgiveness:
[T]he blasphemy against the Holy Spirit consists precisely in the radical refusal to accept this forgiveness, of which he [the Holy Spirit] is the intimate giver and which presupposes the genuine conversion which he [the Holy Spirit] brings about in the conscience. If Jesus says that blasphemy against the Holy Spirit cannot be forgiven either in this life or in the next, it is because this “non-forgiveness” is linked, as to its cause, to “non-repentance,” in other words to the radical refusal to be converted. ... In this way he [the Holy Spirit] brings to completion in human souls the work of the Redemption accomplished by Christ, and distributes its fruits. Blasphemy against the Holy Spirit, then, is the sin committed by the person who claims to have a “right” to persist in evil—in any sin at all—and who thus rejects Redemption. One closes oneself up in sin, thus making impossible one’s conversion, and consequently the remission of sins, which one considers not essential or not important for one’s life. This is a state of spiritual ruin, because blasphemy against the Holy Spirit does not allow one to escape from one’s self-imposed imprisonment and open oneself to the divine sources of the purification of consciences and of the remission of sins. (#46)
This helps us to see that when a person blasphemes against the Holy Spirit, he becomes like the dwarves who find themselves stuck in a dark stable at the end of C.S. Lewis’s The Last Battle. Even when Aslan stands in front of them offering salvation, their only response is to dismiss him as an enemy sent to frighten them.
In this way, the dwarves seal their own fate.
As Aslan explains, “They will not let us help them. They have chosen cunning instead of belief. Their prison is only in their own minds, yet they are in that prison; and so afraid of being taken in that they can not be taken out [of the stable].”
With all that being said, the unforgivable sin against the Holy Spirit is not something that should overly worry us so long as we keep turning to the Lord in repentance.
Indeed, the only heart that cannot receive the Spirit’s forgiveness is the heart that regards the Spirit as something evil and therefore remains closed to His healing grace. As George Herbert wrote, such a heart is harder than any precious gem:
A heart alone
Is such a stone
As nothing but
Thy power doth cut.
Herbert rightly points out, hard though our hearts may be, God’s grace is sharper still.
We therefore should never lose hope either for ourselves or for our neighbor. In the words of St. Thomas Aquinas, “Taking into account God’s omnipotence and mercy, we should despair of no one in this life” (ST I-II.78.3.ad1).
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Further Reading
Pope St. John Paul II, Dominum et Vivificantem
The Deeper Meaning of Pentecost
About Clement Harrold
Clement Harrold earned his master’s degree in theology from the University of Notre Dame in 2024, and his bachelor’s degree in theology, philosophy, and classics from Franciscan University of Steubenville in 2021. He is a columnist for The Catholic Herald, and his writings have appeared in First Things, Word on Fire, Catholic Answers Magazine, Church Life Journal, Our Sunday Visitor Magazine, Crisis Magazine, and the Washington Examiner.
