What is your understanding of the unforgivable/unpardonable sin referred to in these passages? Is it possible for someone who believes in God to commit this sin? Or does the sin essentially refer to the person who has given up on God?
That text has caused an unspeakable amount of misery in the world, for all sorts of people have imagined that they have committed the sin against the Holy Ghost, and though that it would not be forgiven them either in this world or in the world to come. I really do not think that a person with a proper degree of kindliness in his nature would have put fears and terrors of this sort into the world. - Bertrand Russell
I wish I had something more erudite to offer here. I read the Bible as fiction/poetry full of truth but not literal truth "for the letter killeth but the spirit giveth life." In a text as huge as the Bible there is bound to be at least a few lines of bad poetry. But there can be wisdom in bad poetry sometimes. To be Wise is to know ones limits and to know ones limits one must first know that there are limits
...even to forgiveness.
The Holy Spirit is the least comprehensible of the the three components of the trinity. We know what fathers and sons are but what are spirits and how do they relate to fathers and sons. I flirt with the idea that the Holy Spirit is female. The Holy Spirit seems to be more sacred than both (though doctrinally he/she/it is equal) for the Holy Spirit remains a divine mystery even more than the other two.
What is the unforgivable sin? It is the limit. If all is forgivable then all is permitted. We know this not to be true in our heart of hearts. All is not permitted. There are things that we would not permit ourselves to do. Perhaps those verses that speak of the unforgivable sin are not such bad poetry after all. Indeed they may be some of the finest verses in the whole Bible.
Those verses speak of a limit to forgiveness and it is clear that the idea of a limit is necessary. It is possible to go to far. There is a last exit and it is possible to miss the last exit when driving on that proverbial highway to Hell.
If there was no last exit the driver would forever be saying: "I'm doing fine, I'll take the next exit. There is still time."
Perhaps it is good poetry, perhaps bad but rendered into modern parlance this is what it means to me:
Take the next exit.
There is wisdom in recognizing that there is a point of no return.