This was always one of the most confusing and troubling doctrines when I was a JW. I heard the phrase many times, but it was never adequately explained what it meant. I often wondered if I had committed such a sin, and if I could really not be forgiven.
How does one know if they have sinned against the holy spirit? And what makes this sin unforgiveable, as opposed to murder, rape, or any other gross sin?