Then a demon-possessed man who was blind and mute was brought to Jesus, and he healed him, so that the mute man spoke and saw. All the crowds were amazed, and were saying, "This man cannot be the Son of David, can he?"
But when the Pharisees heard this, they said, "This man casts out demons only by Beelzebul the ruler of the demons."
And knowing their thoughts Jesus said to them, "Any kingdom divided against itself is laid waste; and any city or house divided against itself will not stand. If Satan casts out Satan, he is divided against himself; how then will his kingdom stand? If I by Beelzebul cast out demons, by whom do your sons cast them out? For this reason they will be your judges. But if I cast out demons by the Spirit of God, then the kingdom of God has come upon you. Or how can anyone enter the strong man's house and carry off his property, unless he first binds the strong man? And then he will plunder his house. He who is not with Me is against Me; and he who does not gather with Me scatters. Therefore I say to you, any sin and blasphemy shall be forgiven people, but blasphemy against the Spirit shall not be forgiven. Whoever speaks a word against the Son of Man, it shall be forgiven him; but whoever speaks against the Holy Spirit, it shall not be forgiven him, either in this age or in the age to come." [Matthew 12:22-32; NASB]
We find another miracle of Jesus, one wherein he casts out a demon that had rendered a poor man blind and mute (v. 22). This causes the people to wonder if he was the "Son of David" - in other words, the Messiah (v. 23). The Pharisees hear this, and, out of jealousy, come up with the excuse that Jesus is only doing this by the power of Beelzebul (another word for Satan) - in other words, he's casting out demons by using a demonic authority (v. 24). Interestingly enough, the rabbinical sources that speak on Jesus do talk of his miracles, and they too attribute his miracles to witchcraft and demonic power.
Knowing their thoughts, and obviously desiring to nip all this in the bud right away, Jesus addresses them and presents two reasons why their logic does not work:
1) They believed demons were pitted against demons (vv. 25-26) - While it is possible for exorcisms to be faked by demons (for we cannot assume that Muslim or Hindu exorcisms are legitimate, as demons fear no one but the true God), the Pharisees were not arguing that Jesus was in league with the demons to create ruses, but rather that Jesus was using a higher demonic authority to expel demons who were going about their job. By this logic, Satan's house was divided, and there was a demonic civil war going on. This is what Jesus means by "If Satan casts out Satan, he is divided against himself; how then will his kingdom stand?" Later on, in verse 29, Christ will give a more accurate view of the situation: it is actually another, non-demonic power at work against the demonic powers.
2) They had disciples who exorcised demons too (v. 27) - Jesus was not the only one known to cast out demons, though he was certainly the only one to cast them out of his own authority and by his own command. In any case, the Pharisees did not attribute every single exorcism to demonic power, but were seeking to disprove Christ's Messianic status. When Christ says "they will be your judges," he does not necessarily mean that the other Jewish exorcists will stand up and judge them, but rather that the Pharisees' hypocrisy in holding up Jesus to one standard and the other exorcists to another standard will be used against them when they are judged. To explain this phraseology, imagine if someone says, "This video tape that recorded your crime will condemn you." This doesn't mean the video tape is going to bang a gavel and pronounce sentencing, it simply means the video tape will be a damning piece of evidence used in the court of law.
Having proven this logic does not work, Christ now presents the only conclusion: "If I cast out demons by the Spirit of God, then the kingdom of God has come upon you" (v. 28). In other words, Christ's exorcisms were part of the prophecies foretold about the Messiah, and what expelled the demons was not Satan, but God the Holy Spirit, working with God the Son in accordance with the Trinitarian work. Note that earlier (see vv. 17-21), Matthew had quoted Isaiah 42:1-4, which said that God's "Beloved" (the Messiah) had had the Spirit placed upon him, and he would do all the work he was meant to do. This story is one such example of Christ fulfilling that. The people in verse 23 were correct - Christ was the Son of David. And he was proving that by the work of the Spirit against the demons.
Here now, during Christ's response, we have the mention of the "unpardonable sin." Christ outlines that those who are not with him are against him (so much for inclusivism!) and those who are not gathered with him scatter (v. 30). There is no neutrality. Christ is drawing a line in the sand at this point, for both the benefit of the people listening and the Pharisees. He takes it even further by saying that all sin and blasphemy shall be forgiven, but "blasphemy against the Spirit shall not be forgiven" (v. 31), going on to say that "whoever speaks a word against the Son of Man, it shall be forgiven him" - but those who speak "against the Holy Spirit" will not be forgiven either "in this age or in the age to come" (v. 32). For many who quote these few verses in isolation, they come to similar erroneous conclusions:
1) The Post-Death Judgment Error - Some believe that this means that God will forgive sins after a person dies. What they do is they take the "either in this age or in the age to come" and read it backwards into "it shall be forgiven him." The problem with this is two fold: a) Christ is not arguing that some sins can be forgiven after death, only that the blasphemy against the Spirit is very serious - he's emphasizing how gosh darn serious it is by adding "either in this age or in the age to come" to demonstrate it; b) the "ages" here refer more so to the pre-Messianic age and the Messianic age - that is, Jews of Christ's time had in mind that you would have the old covenant, then the coming of the Messiah, and then the new age under the Messiah's rule. This is how Christ's listeners would have understood it.
2) The Hyper-Charismatic Error - Some in the Hyper-Charismatic and Neo-Pentecostal camp have taken these verses to mean that any time you point to a supposed work of the Holy Spirit (a miracle healing, speaking in tongues, prophecy, etc.) and say "That's not the Holy Spirit," that automatically means you're blaspheming the Holy Spirit. This can't be the case, as scripture is quite clear that we should be on the lookout for demonic counterfeits of spiritual work: Pharaoh's magicians could mimic many of the miracles of God (Ex 7:11, 22; 8:7); the Law warned against those who would perform miracles and wonders and yet attempt to lead you astray from the orthodox path (De 13:1-4); Jesus warned against false christs and prophets who would perform miracles (Mt 24:24); the apostle Paul warned that the "lawless one" would perform signs and wonders (2 Th 2:9-10); the beast in Revelation is described as performing signs and wonders (Re 13:13-14). Declaring something to not be the work of the Spirit, especially when we have grounds to do so, is not in and of itself blasphemy against the Spirit, but just good discernment.
So, what is this verse talking about? Well, let's remember some of the preliminary information given us, and try to follow the flow of the narrative: Jesus, as Messiah, has the Spirit (v. 18); the people are wondering if Jesus is the Messiah, but the Pharisees are denying it (vv. 23-24); Christ states that his work is by the Spirit, which means the kingdom of God has come upon them (v. 28); he then states that blasphemy against the Son of Man will be forgiven, but not blasphemy against the Spirit (vv. 31-32). What then is Christ talking about in these two verses?
It is clear, from the context, that Christ is stating that, when all is fulfilled (that is, the Messianic age has come, and Christ is glorified after the resurrection), those who continue to deny his divine status and role as Messiah, just as they were then, will be condemned. Many "spoke a word" against Jesus as the Son of Man (such as Peter) but were later forgiven, especially at Pentecost and other events recorded in Acts. Most of the Pharisees, however, continued to work against him and denied not only his messianic status, but his divinity - first during his earthly ministry, and then against his church. This is even more clear in Mark's parallel account, where (after the blasphemy against the Holy Spirit is spoken of) Mark adds that Jesus said all this "because they were saying, 'He has an unclean spirit'" (Mk 3:30). In denying that Christ's power and miracles were by the Spirit, and attributing it to demonic powers, the Pharisees were blaspheming the Spirit and working against the kingdom of God. It was a sign of their heart (hence Christ's stern warnings about the connection between the heart and words in vv. 33-37, following the "blasphemy of the Holy Spirit" verses) and that they were, in essence, marked off for condemnation.
This has led many theologians and commentators to argue that, really, the "blasphemy of the Holy Spirit" is no longer relevant for this day. That is, it was only relevant to those who lived during Christ's time, during that tender moment between the two ages, when one could blaspheme the Son of Man but not blaspheme the Holy Spirit. If we were to apply it today somehow, it would, in a sense, be similar to those who, upon hearing of Christ's miracles, attempt to write them off as exaggerations, lies, sorcery, magic tricks, or the like. We should not, however, use these verses to write these people off as damned, and we should treat them with respect and love, and give them the same message of hope and reconciliation which God used to call us. There are many who denied Christ's miracles today who later repented and put their trust upon the Lamb.