31 “Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. 32 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 (cf. Mark 3:22,28-30).
The Pharisees commit the unpardonable sin by blaspheming against the Holy Spirit (v.24; cf. Mark 3:29). They attribute God’s work to Satan. They deliberately associate the power and the work of Jesus, who is full of the Holy Spirit, with the work of Satan. This is to equate supreme spiritual good with supreme spiritual evil, hardening their hearts in a way that makes repentance and forgiveness impossible. They are thus beyond redemption.
Jesus categorically states that every sin and blasphemy will be forgiven, even if it is spoken against the “Son of Man”, but if anyone speaks against the Holy Spirit will never be forgiven.
Speaking against the Spirit, calling the work of the Spirit the work of Satan, involves an explicit, willful, and decisive rejection of the very Power that can bring about repentance. The notion of the “unforgivable sin” has caused needless anxiety. Anyone who has been convicted of sin by the Spirit (John 16:8) and now believes the truth cannot possibly have committed it. (Adapted from RSB.)
These are profound thoughts and worthy of careful consideration.