What is the unforgivable sin? And how, if at all, is it applicable to our own situation?
The unforgivable sin comes to us in two different versions:
i) In the Marcan/Matthean version (Mt 12:31-32; Mk 3:28-29), it has reference to attributing dominical exorcisms to sorcery.
ii) In the Lucan version (Lk 12:10), it has reference to apostasy under threat of persecution.
We presumably have two different versions because Jesus spoke to the issue on at least two different occasions.
This should warn us against equating the unforgivable sin with the specific circumstances in which it is described, for—as the Synoptics illustrate—the circumstances vary.
So what do these two descriptions have in common?
i) In both cases, the sinner is in a position to know better.
ii) Another possible point of contact is that, in both cases, we’re dealing with public testimony. The Jewish opponents publicly denounce the ministry of Christ. The persecuted believer publicly renounces the faith.
What makes the sin unforgivable? It is possible that (i) is a sufficient condition.
But it may also be that (ii) furnishes a necessary, aggravating circumstance.
On that view, what makes it unforgivable is not simply that the sinner is in a position to know better, but that he is dissuading others from believing in Christ.
In the case of the Jewish opponents, the sinner is bearing public witness against the work of Christ.
In the case of the apostate, his recantation is a public witness against the mission of Christ.
And even if his recantation is an act of cowardice rather than conviction, the effect of his example is dissuasive.
Or it may be that (ii) is a sufficient condition in its own right.
Remember that, in Scripture, the presumption is that, all other things being equal, sinners are lost. It’s not that you have to do something extra-special to be on the road to perdition.
You don’t need to take a wrong turn, for, absent the grace of God, you are already headed in the wrong direction.
How do we account for the distinction between blasphemy against Jesus, which is forgivable, and blasphemy against the Spirit, which is unforgivable?
i) To begin with, the work of the Spirit, in context, has immediate reference to exorcism, although it would presumably include miracles more generally, of which exorcism is a subset.
This thaumaturgical work is not to be confused with the internal witness of the Spirit.
ii) The distinction likely differentiates between corroborated and uncorroborated testimony. Christ bears witness to himself, but his self-testimony is seconded by the prophets as well as the work of the Father and the Spirit as they empower him to perform miraculous deeds. The Resurrection would be the capstone.
iii) If (ii) is correct, then the point is not that blasphemy against the Spirit is intrinsically more heinous than blasphemy against the Son. The distinction is not between the Spirit, per se, and the Son, per se—but between the testimony of Christ, alone, and the corroborative work of the Spirit.
How does this apply to our own situation?
We need to avoid two extremes:
i) For the above-stated reasons, it’s a mistake to limit the unforgivable sin to the specific circumstances in which it is described. These circumstances occasion the teaching, but the sin cannot be tied down to the illustrative exigencies.
ii) If (i) is overly narrow, the opposite error is an overly broad application in which the unforgivable sin is simply equivalent to persistent unbelief. That application is so generic that it fails to explain why this particular sin is singled out, in contrast to other sins, as unforgivable. So it needs to meet stricter criteria.
iii) On a minimalist interpretation, the unforgivable sin would satisfy two conditions:
(a) The sinner is in a position to know better, and:
(b) He goes public with his disbelief to dissuade others.
Both (a) and (b) would be necessary conditions, but insufficient in isolation.
iv) On a maximalist interpretation, the unforgivable sin would satisfy only one condition: (a) or possibly (b).
On that view (a) would be a sufficient condition.
It’s possible that (b) would also be a sufficient condition.
v) In Scripture, there is also a distinction between apostates and backsliders. A professing believer can suffer a lapse of faith, but be restored to the faith.
He may have been a true believer who suffered a crisis of faith or loss of nerve, or else he may have been a nominal believer who, as a result of his temporary defection and restoration, becomes a true believer.
So who can commit the unforgivable sin? Depending on our interpretation, an apostate, a public enemy of the faith, and/or someone who never made profession of faith, but is in a position to know better.
It isn’t necessary for us to draw the exact boundaries, for the larger lesson is that no one should go anywhere near the point of no return.
It isn’t a question of knowing where the invisible line is drawn, and then doing everything just up to the trip-wire without stepping on the spiritual land-mine. For that attitude is already a damnable attitude.