The Bible says everything can be forgiven, except one sin - and no one I have ever talked to can even explain how you commit that sin (blasphemy against the Holy Spirit).
“and no one I have ever talked to can even explain how you commit that sin (blasphemy against the Holy Spirit). “
It’s denying the work of the Holy Spirit. It was originally a condemnation of those who returned to Judaism.
Blasphemy Against The Holy Spirit: Matthew 12:31--By accusing Jesus of being in league with Satan when he was really acting through the power of the Holy Spirit, they had blasphemed the Spirit, hardening their hearts against the Spirit's influence.
-- In Mark's account, Jesus called it an "eternal sin" (3:29). As long as a person persists in this state, genuine repentance is impossible. There is no room in this person's heart for penitence, which is a prerequisite for forgiveness. His sin is unpardonable simply because he is unwilling to travel the road that leads to pardon. The only sin that God is unable to forgive is the unwillingness to accept forgiveness.
Try this and let me know what you think as an explanation
http://lesfeldick.org/lesqa-c.html#6c
My opinion, for what it is worth, is that it is dying without Christ.
The one unforgivable sin is understandable from the context in which Jesus made that statement (Matthew 12:22-32). The Pharisees saw him casting out demons and said he did it by the power of Be-el'zebul the prince of demons. Therefore, the unforgivable sin is a sin of attribution: it is to see the work of God and tell people it is the work of the devil.