Jesus issued a solemn warning to a group of Jewish leaders who accused Him of performing miracles by the power of Satan.
“Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come” (Matthew 12:31-32 NKJV).
Jesus knew that there would be many who wouldn’t recognize Him as the promised Messiah. Many would reject Him out of ignorance or false expectations. The first words He spoke from the cross make it apparent that such people could be forgiven:
“When they had come to the place called Calvary, there they crucified Him, and the criminals, one on the right hand and the other on the left. Then Jesus said, ‘Father, forgive them, for they do not know what they do’ ” (Luke 23:33-34 NKJV).
This is why He said that someone who spoke a word against the Son of Man could be forgiven.
Yet because Jesus was approved by the Father (Matthew 3:13-17), was directed and empowered by the Holy Spirit (Luke 4:1,14,18-21), and cast out demons and performed miracles as signs of the kingdom of God (Matthew 12:28), there was great danger in attributing His acts to the devil. The danger was that rejection of Jesus was an indication not of misunderstanding or ignorance, but of willful, malevolent opposition to the Spirit of God. Such willful opposition could lead to irreversible hardening of the heart.
Sometimes people who curse God in a moment of despair think of Jesus’ warning about the blasphemy against the Holy Spirit and are gripped by a satanic obsession that their sin is unforgivable. (See the ATQ article, When we feel guilty, how can we know whether the Holy Spirit is convicting us or Satan is accusing us?) This is a shame, considering the fact that their very repentance (or desire for repentance) is a demonstration of the fact that the Holy Spirit is still working in their lives.
A good example is Peter.
Jesus had given a somber warning to His disciples: “Whoever acknowledges me before men, I will also acknowledge him before my Father in heaven. But whoever disowns me before men, I will disown him before my Father in heaven” (Matthew 10:32-33 NIV).
Peter was brash and confident that he would never deny his Lord: “Peter declared, ‘Even if I have to die with you, I will never disown you.’ And all the other disciples said the same” (Matthew 26:35 NIV).
Jesus knew Peter’s weakness much better than Peter did, and told him: “ ‘I tell you the truth,’ Jesus answered, ‘this very night, before the cock crows, you will disown me three times’ ” (v.34 NIV).
Jesus was right. Peter not only denied his Lord, but he also denied Him with curses. “Then he began to call down curses on himself and he swore to them, ‘I don’t know the man!’ Immediately a cock crowed” (v.74 NIV).
The sin against the Holy Spirit is a consistent and continual denial of the truth, hardening one’s heart against God and His revelation of Himself in Christ. No one has committed the sin against the Holy Spirit if he or she is concerned about having committed it. A person who sins against the Holy Spirit has no love for God or any desire to be reconciled to Him.
If you are concerned about the wrong you have done, you are eligible for forgiveness. Just like Peter, David, and Paul (who were likely greater sinners than you), your sins are forgiven the moment you confess them and cast yourself on the mercy of God through the blood of Jesus Christ.