Oracle: I'd ask you to sit down, but, you're not going to anyway. And don't worry about the vase.
Neo: What vase?
Neo turns to look for a vase, and as he does, he knocks over a vase of flowers, which shatters on the floor.
Oracle: That vase.
Neo: I'm sorry...
Oracle: I said don't worry about it. I'll get one of my kids to fix it.
Neo: How did you know?
Oracle: Ohh, what's really going to bake your noodle later on is,
would you still have broken it if I hadn't said anything?
-The Matrix (1999)

So what provoked Jesus into saying that blasphemy of the Holy Spirit is the only unpardonable sin? To understand, it may help to juxtapose his comment within ancient Biblical history where the scribes and priests had really been looking for a way to kill Jesus. Not only has Jesus healed on the Sabbath, he had told the parable of the wicked tenants, a story directly aimed at the Pharisees. It’s a simple story. A landowner leases his vineyard to a band of tenant farmers and leaves. While he is gone, the tenants begin to act like they own the place. When the owner sends a servant to collect payment, the tenants send him back without the rent. When the servant comes back again, they beat him up and throw him out. At last, the landowner sends his son, believing that surely the tenants will pay attention to him. But, no — they drag him off of the land and kill him, thinking that will make the vineyard theirs for good. 1 2 This of course is all an insinuation aimed at honking off all of the community leaders on behalf of the Jewish people. The vineyard is Israel, the servant is God’s people, and the tenants are the priests, the landowner, God; his son, Jesus and so on. The economics and politics of the era also played a large part in the perspective of what the audience was hearing in the story:

The parable…reflects … economic realities of Roman Palestine (in) the parable of the Wicked Tenants… specifically the condition of widespread unemployment in Galilee. Large segments of the population had been dispossessed and reduced to destitution, as a result of Pompey's reorganization of Palestinian territory. At the same time Herod the Great's expropriation of large tracts of farmland, sold to wealthy landowners or distributed to the officials of his court, had intensified the process... consequently peasants and tenants...who depended on them, had only their labor to sell to anyone who wished to hire them.

So the Jewish people made their living as servants of the politicians and the parable was pointed at them as well. The gospel of Luke goes on to note, "The teachers of the law and the chief priests looked for a way to arrest him immediately, because they knew he had spoken this parable against them."

This became the enemy of my enemy is my friend scenario and motivated the Pharisees to conspire with the Herodians because Jesus has not only ostracized many leaders in the secular community-- he had stigmatized the Jewish leaders as falling short of the law. Add to the mix that, without fail Jesus has demonstrated compassion by supporting those who were considered the dregs of society and hence marginalized by the temple advocates. This event sets the stage for the Passion and quickly culminates in the crucifixion.

During Passover Jesus foretells of his betrayal then he and his inner circle adjourn to the Mount of Olives. Near midnight the betrayal comes and Jesus is led away by the chief priests, elders, and scribes. When Jesus is asked directly if he is the Messiah, he replies with an allusion to Daniel, "I saw one like a human being coming with the clouds of heaven. And he came to the Ancient One and was presented before him. To him was given dominion and glory and kingship that all peoples, nations, and languages should serve him. His dominion is an everlasting dominion that shall not pass away, and his kingship is one that shall never be destroyed." The high priests interpret this as blasphemy. According to the Oxford Companion, blasphemy is defined as, “Speech that is abusive to humans or derogatory to God. Blasphemy against humans occurs when people speak words harmful to one another.” 3 4 The Old Testament law of Leviticus says that it is punishable by death.

When it comes to the unpardonable sin, the passages that has brought forth a great deal of debate is written about by both Matthew and Mark. Jesus tells his persecutors that to speak blasphemy against the Holy Spirit is the sin that cannot be forgiven. As he brings this to the attention of the priests, he points out that this sin is not committed inadvertently by Jesus’ followers, but is attributed directly to the enemies of Jesus, who were claiming that his popularity among his followers was due to an evil spirit. The Pharisees, claiming divine prerogative, interpret the Levitical law that because Jesus is claiming to be the Messiah he deserves death. Jesus’ retort is that by destroying what has been built up by the Holy Spirit in the persona of his followers, their actions risk an unpardonable sin because they are alienating Israel from God. In an effort to retain their authority the Pharisees take Jesus before Pontius Pilate and he is subsequently convicted and crucified. Two thousand years later people are still talking about it.

Sources:

Intimations of the Year of Jubilee in the Parables of the Wicked Tenants :
www.religion-online.org/showarticle.asp?title=28

Interpretation:
crain.english.mwsc.edu/Mark/interpre9.htm

Memorable Quotes from The Matrix (1999):
www.imdb.com/title/tt0133093/quote

The Oxford Companion to the Bible, 1993, p.92

The Parable of the Wicked Tenants:
www.discipleship.net/parable/wickedtenants.htm