In three parallel passages in the Gospels, Jesus speaks of sin against the Holy Spirit: Matthew 12:31-32, Mark 3:28-29 and Luke 12:10. St. Luke’s version is the most succinct: “Everyone who speaks a word against the Son of Man will be forgiven, but the one who blasphemes against the holy Spirit will not be forgiven.”
The first clause of this sentence reminds us that a person who is mistaken about Jesus, who does not know Jesus as the Son of God, can be forgiven for not acknowledging Him.
To understand the second clause, we must first note a basic truth: God limits himself with regard to human freedom. Though He always includes in His overall plan even our misuse of our freedom, He always respects that freedom and will not destroy it.
He therefore does not force himself on us, so to speak – does not force us to accept His love and forgiveness. Our freedom gives us the frightful capacity to reject Him and to refuse to allow Him to forgive us.
The “unforgivable sin” is the sin of refusing to be forgiven. It is the determination to continue in sin at all costs.
In his encyclical Dominum et Vivificantem (“Lord and Giver of Life,”1986), Pope John Paul II taught: “If Jesus says that blasphemy against the Holy Spirit cannot be forgiven either in this life or in the next, it is because this ‘non-forgiveness’ is linked, as to its cause, to ‘non-repentance,’in other words to the radical refusal to be converted” (no. 46).
Sometimes sincere Christians ask themselves whether in fact they have committed the unforgivable sin. If one asks that question in awe and even in fear, the very asking shows that a person has not committed the unforgivable sin.