Can God's grace cover even the sin of blasphemy against the Holy Spirit?
Yes, God's grace reaches beyond every sin, including blasphemy against the Holy Spirit. That blasphemy is still sin, yet the vilest sinner remains a candidate for grace. The necessary response is belief, for unbelief is what condemns; grace extends beyond spoken sins.
Les explains that people often fear they have committed the unpardonable sin, which most associate with blasphemy against the Holy Spirit. He acknowledges that blasphemy against the Holy Spirit is a sin, and the unpardonable sin means no hope of glory. Yet he says that if Scripture is understood correctly, no sin is beyond God's grace; the vilest sinner is still a candidate for grace. The only thing that condemns Jew or Gentile is unbelief, and the sinner's required response is to believe. He then turns to Hebrews 3, where Israel came out of Egypt and God led them toward the promised land, to make the point from the reverse end.