There is a lot of confusion over the term unpardonable sin. The phrase does not actually appear in the Bible but it is implied in Matthew 12:31-32.
“And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven. Anyone who speaks a word against the Son of Man will be forgiven, but anyone who speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.”
While grace and forgiveness are found throughout the Bible, we can’t simply ignore this passage in light of what the Bible says about forgiveness elsewhere. We know that there are no contradictions in the Bible so we must work hard to discern what this statement by Jesus means.
To start, we should note the context of Jesus’ statement. He was performing miracles and casting out demons. The Pharisees accused Jesus of performing miracles with the power of Satan. Attributing the work of the Holy Spirit to Satan is what Jesus calls blasphemy against the Spirit.
Jesus makes it clear that “every sin and blasphemy will be forgiven” which is in line with everything else that the Bible teaches. Jesus includes a “but” along with His statement though. He says that anyone who speaks against the Holy Spirit will not be forgiven.
Some say that blasphemy of the Holy Spirit is simply hypothetical because there is no sin that a person can commit that is unforgiveable. But let’s assume that Jesus is not speaking hypothetically and that this is a real sin that people commit. This is not an accidental sin or even one that is intentionally committed. Instead what Jesus is addressing is a matter of someone’s heart being so hard that they refuse to even acknowledge the work of God and instead attribute it to Satan.
Some Christians believe that salvation can be lost and others believe that there is eternal security. This passage does not address either belief however. This is not a sin that a Christian will commit. While Christians are still capable of lots of terrible sins, their hearts will never become so hard as to call the work of the Holy Spirit Satanic.
It is worth noting that Jesus says “will not be forgiven” rather than “cannot be forgiven.” It is perhaps key to our understanding of this passage and to our understanding of God’s forgiveness. It seems arbitrary that God would choose to hold one sin as unforgiveable in light of all of the other terrible things that a person can do. But when we look at this as a matter of the heart it makes sense. A person who is so far gone as to blaspheme the Holy Spirit will not be forgiven because they will never seek forgiveness. It is not that God’s grace is incapable of forgiving the person. Instead it is a sign that the person has no interest in forgiveness. The next verse gives us an indication of this.
“Make a tree good and its fruit will be good, or make a tree bad and its fruit will be bad, for a tree is recognized by its fruit.” The fruit of the Spirit will be evident in the life of a Christian. Blasphemy of the Holy Spirit is the fruit of a life that is so far from God that the person will never seek forgiveness.
So the unforgiveable sin comes down to a matter of human will and not the ability of God. God is still capable of forgiving any and all sins. The Pharisees that Jesus is addressing have hearts that are so hard that they will never seek God in repentance however. This is not a sin that a Christian can or would commit. In fact only the most non-Christians will never be so far removed from God to commit this sin.