The mere fact that people anxiously ask whether they have committed the unforgivable sin reveals that they most surely haven’t. If they had committed it, they certainly wouldn’t be worrying about it. Their worry is all the evidence they need that, indeed, they are still open to the Spirit’s leading.
What the person should do is claim the righteousness of Jesus and, clinging to Jesus’ merits, press on ahead in faith and obedience. Only under the covering of Christ’s righteousness, which is the “righteousness of God” Himself (Rom. 10:3), can they have the peace and assurance that they so sorely lack now.
There is, really, only one person God cannot forgive, and that is the person who persistently refuses to come to Jesus for forgiveness. “The sin of blasphemy against the Holy Spirit does not lie in any sudden word or deed; it is the firm, determined resistance of truth and evidence.” – Ellen G. White Comments, The SDA Bible Commentary, vol. 5, p. 1093. “No one need look upon the sin against the Holy Ghost as something mysterious and indefinable. The sin against the Holy Ghost is the sin of persistent refusal to respond to the invitation to repent.”-Page 1093.