Anyone who spends a little time reading Scripture eventually comes across the troubling warning from Jesus in verses 28 and 29 of our text from Mark 3:20-30. And for sensitive souls the worry ensues, “Have I committed the unforgivable sin?”
Reading the warning in context makes it clear that the unforgivable sin is the attitude of ascribing God’s good work of salvation in Christ to spiritual forces of evil. Mark very clearly explains in verse 30 that the scribes had committed or were on the verge of committing “blasphemy against the Holy Spirit” by attributing the work of God’s Spirit to demonic forces (Beelzebul in verse 22).
The standard answer to worries about committing this unforgivable sin is correct. If you are worried about it, you haven’t done it. That is, if there is enough fear of God in you to be concerned about how He would judge your sin, then your spiritual state is not and never was in the bleak condition which identifies something good as something evil.
Blasphemy against the Holy Spirit–in the form of seeing the work of Christ as evil–is unforgivable because it removes one from the possibility of salvation. The very thing which saves, the work of God in Christ, is denied and falsely judged and salvation becomes impossible.
Actually, in the process of delivering the warning about the unforgivable sin, Jesus offered the utmost reassurance about forgiveness in verse 28, “Truly I tell you, people will be forgiven for their sins and whatever blasphemies they utter…” That is, everything is forgivable except denying the possibility of forgiveness by seeing Jesus who brings forgiveness as possessed by an evil spirit.
So all the sins Christians have sometimes treated as though they were unforgivable–murder, adultery, divorce, etc.–are within the scope of grace. The true wideness of God’s mercy and forgiveness is revealed as we contemplate the very narrow field of what is unforgivable.