Let me begin with my thoughts then conclude with some quotations:
Let's first look through the lens of trinitarian theology. We know that trinitarian theology affirms the unity of the Father, Son, and Holy Spirit as distinct persons within the one Godhead. That being said, while they are inseparable in their essence and divine nature, they are distinguishable in their roles and relationships. If we don't make this distinction, then I don't think we'll be able to see how blasphemy against the Holy Spirit may differ from blasphemy against the Father or the Son.
Some interpret this as a sin of final impenitence. Unlike sins against the Son of Man (Jesus), which perhaps could be forgiven through repentance, blasphemy against the Holy Spirit represents a persistent refusal to acknowledge the work of God's Spirit, thus rendering forgiveness unattainable.
We know that Father, Son, and Holy Spirit are equal in their divine nature, however, they are different in their roles in our salvation. The Son became flesh, lived among us, and provided the atoning sacrifice for sin through His death and resurrection. The Holy Spirit, is responsible for our conviction, our regeneration, and our sanctification, working in our hearts for our transformation. Blasphemy against the Holy Spirit may be understood as a rejection of His convicting and transforming work, thereby rejecting the very means of salvation.
Benson Commentary:
By the blasphemy here spoken of, we are evidently to understand
injurious or impious speaking against the Spirit of God, such as the
Pharisees were now guilty of; that is, attributing to the devil those
miracles which Christ gave full proof that he wrought by the Holy
Spirit.
Ellicott's Commentary for English Readers:
But to see a man delivered from the power of Satan unto God, to
watch the work of the Spirit of God, and then to ascribe that work
to the power of evil, this was to be out of sympathy with goodness
and mercy altogether. In such a character there was no opening for
repentance, and therefore none for forgiveness.
Barnes' makes a different point.
Barnes' Notes on the Bible:
In this place, and in Mark 3:28-30, Jesus states the awful nature of
the sin of which they had been guilty. That sin was the sin against
the Holy Spirit. It consisted in charging him with being in league
with the devil, or accusing him of working his miracles, not by the
"spirit" or "power" of God, but by the aid of the prince of the
devils. It was therefore a direct insult, abuse, or evil speaking
against the Holy Spirit - the spirit by which Jesus worked his
miracles. That this was what he intended by this sin, at that time, is
clear from Mark 3:30, "because they said he had an unclean spirit."
All other sins - all speaking against the Saviour himself - might be
remitted. But this sin was clearly against the Holy One; it was
alleging that the highest displays of God's mercy and power were the
work of the devil; and it argued, therefore, the deepest depravity of
mind. The sin of which he speaks is therefore clearly stated. It was
accusing him of working miracles by the aid of the devil, thus
dishonoring the Holy Spirit.
He continues later:
Speaketh against the Holy Ghost - The word "ghost" means "spirit," and
probably refers here to the "divine nature" of Christ - the power by
which he performed his miracles. There is no evidence that it refers
to the third person of the Trinity; and the meaning of the whole
passage may be: "He that speaks against me as a man of Nazareth - that
speaks contemptuously of my humble birth, etc., may be pardoned; but
he that reproaches my divine nature, charging me with being in league
with Satan, and blaspheming the power of God manifestly displayed "by
me," can never obtain forgiveness."
Gill's Exposition of the Entire Bible:
but the blasphemy against the Holy Ghost, shall not be forgiven unto
men: by which is meant, not every ignorant denial of, and opposition
to his deity and personality; nor all resistance of him in the
external ministry of the word; nor every sin that is knowingly and
wilfully committed; but it is a despiteful usage of the Spirit of
grace, an opposing, contradicting, and denying the operations wrought,
or doctrines revealed by him, against a man's own light and
conscience, out of wilful and obstinate malice, on purpose to lessen
the glory of God, and gratify his own lusts: such was the sin of the
Scribes and Pharisees; who, though they knew the miracles of Christ
were wrought by the Spirit of God, yet maliciously and obstinately
imputed them to the devil, with a view to obscure the glory of Christ,
and indulge their own wicked passions and resentments against him;
which sin was unpardonable at that present time, as well as under that
dispensation then to come, when the Spirit of God was poured down in a
more plenteous manner.
