Blasphemy against the Holy Ghost

What specifically is the unpardonable sin? What does it mean to blaspheme against the Holy Ghost?

The most fateful words ever spoken by Jesus had to do with the fearful possibility of committing the unpardonable sin. He said:

Matthew 12:31, "Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men."

Mark 3:28-30, "Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme: But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation: Because they said, He hath an unclean spirit."

Luke 12:10, "And whosoever shall speak a word against the Son of man, it shall be forgiven him: but unto him that blasphemeth against the Holy Ghost it shall not be forgiven."

No one can misconstrue the clear message of these verses. There is a sin unto death. A man or woman may pass over a line which separates God's mercy and His wrath and not be able to come back. What is this sin which Heaven regards with such abhorrence and loathing? Why will God deal so severely with those who are guilty of this sin? To the human mind a great number of depraved and cruel acts might fall into such a category but which one of them would God count so heinous and horrible that it could never be forgiven?

By looking at these verses in context, and reading the few verses just before Jesus says "blasphemy against the Holy Ghost shall not be forgiven," we can understand its meaning.

Matthew and Mark's Passage

First, let's take a look at the book of Matthew and Mark. You will notice that, in these passages, the Pharisees accused Jesus of casting out demons in the name of Beelzebub the prince of the devils (Matthew 12:22-30, Mark 3:22-27). This is the context in Matthew and Mark just before Jesus spoke about the unpardonable sin.

In other words, what Jesus meant by this phrase is this: when a person attributed those works to the devil, which he had the fullest evidence could be wrought only by the Spirit of God, that this, and nothing else, is the sin against the Holy Ghost. This is evident from Mark 3:30! Right after Jesus said blasphemy against the Holy Ghost would not be forgiven, Jesus stated the reason:

Mark 3:30, "Because they said, He hath an unclean spirit."

Here the matter is made clear beyond the smallest doubt. The unpardonable sin, as some term it, is neither less nor more than ascribing the miracles Christ wrought by the power of God, to the spirit of the devil. No man who believes the Divine mission of Jesus Christ, ever can commit this sin.

Luke's Passage

Now, let's look at the book of Luke. Just before Jesus says "but unto him that blasphemeth against the Holy Ghost it shall not be forgiven" in verse 10, Jesus said the following:

Luke 12:8-9, "Also I say unto you, Whosoever shall confess me before men, him shall the Son of man also confess before the angels of God: But he that denieth me before men shall be denied before the angels of God."

Again, this passage confirms that whoever "denies" Jesus before men will not be forgiven. The way one does this is by denying that the miracles Christ did was by the power of God, and ascribing his miracles to the spirit of the devil. However, this applies only to those who are knowledgeable about God. Those who do this sin in ignorance, before they truly learn about God, will be forgiven if they later confess and repent (Genesis 20:3-6, Luke 12:47-48, Acts 17:30, Romans 2:12-15, Hebrews 5:2, James 4:17). Sin will only be counted against those who have heard truth and rejected it (John 9:41; 15:22).

From Adam Clarke's Commentary

The sin here spoken of by our Lord ranks high in the catalogue of presumptuous sins, for which there was no forgiveness under the Mosaic dispensation (See Deuteronomy 1:43; 17:12-13, Numbers 15:30; Leviticus 20:10). When our Lord says that such a sin hath no forgiveness, is he not to be understood as meaning that the crime shall be punished under the Christian dispensation as it was under the Jewish, viz. by the destruction of the body? And is not this the same mentioned in 1 John 5:16, called there the sin unto death; i.e. a sin that was to be punished by the death of the body, while mercy might be extended to the soul? The punishment for presumptuous sins, under the Jewish law, to which our Lord evidently alludes, certainly did not extend to the damnation of the soul, though the body was destroyed: therefore I think that, though there was no such forgiveness to be extended to this crime as to absolve the man from the punishment of temporal death, yet, on repentance, mercy might be extended to the soul; and every sin may be repented of under the Gospel dispensation.