" I tell you the truth, everyone who acknowledges me publicly here on earth, the Son of Man will also acknowledge in the presence of God's angels. But anyone who denies me here on earth will be denied before God's angels. Anyone who speaks against the Son of Man can be forgiven, but anyone who blasphemes the Holy Spirit will not be forgiven." - Luke 12:8-10
Here is what the Life Application Bible Commentary says about verse 10-"But whoever blasphemes against the Holy Spirit—who continually rejects the Holy Spirit's message about Jesus and his convicting influence to believe in him—is beyond redemptive help. The rejection of the messenger (even of the Son himself) can be forgiven, but not the rejection of God himself through the Holy Spirit. The mighty works done by the Spirit were unmistakable announcements that the kingdom had arrived. Jesus said that those who blasphemed the Holy Spirit will not be forgiven--not because that sin is worse than any other, but because they will never ask for forgiveness.