Jesus' announcement that blaspheming the Holy Spirit is a sin that will never be forgiven is "hard" for two reasons. First, it seems to contradict Scriptures that tell us Christ's blood can effect forgiveness for every sin (1 John 1:7, 9). Second, Jesus affirms that slander against Himself, the Son of Man, can be forgiven; but slander against the Holy Spirit cannot. Does this exalt the dignity of the third person of the Trinity above the second person? The saying appears in varying forms in the Gospels:
Every sin and blasphemy will be forgiven people, but the blasphemy against the Spirit will not be forgiven. (Matt. 12:31)
Only Mark explains why this sin is unforgivable: Jewish scribes were attributing to Satan (Beelzebul) the Holy Spirit's power by which Jesus was expelling demons. What sets the slander of the Spirit apart from forgivable sins is the knowledgeable and willfully rebellious mind-set of the scribes. Their charge that Jesus derived His power over demons from His alliance with their evil prince was patently absurd. As Jesus pointed out, Satan is not so foolish as to war against himself. Only the scribes' resolve to contradict what they knew full well to be true could move them to utter such an accusation. In the face of indisputable evidence that in Jesus, God's Spirit was establishing God's kingdom and defeating Satan's, they hardened their hearts to a point of no return. Paul, though once "a blasphemer ... acted ignorantly in unbelief" (1 Tim. 1:13). His ignorance did not excuse him, but it left his heart permeable to the Spirit's invasion.
Forgiveness is possible for one who slanders the Son not because any of the three divine persons has less glory than the others. Rather, the Son's incarnation veiled His glory in ways that obscured it from the view of many who were blinded by ignorant unbelief but were still recoverable by the Spirit.
Of two truths we may be sure: None who commits this unforgivable sin will ever trust in Christ to receive the forgiveness found in Him. And no one who flees to the crucified and risen Son of Man has committed that heinous slander of the Spirit—nor will the Savior turn away anyone who turns to Him.