To commit the fundamental sin is to knowingly infringe the free will of other souls for one’s own benefit.

It’s hard to be forgiven for this fundamental sin.

It’s even harder to be forgiven if you commit it with your own free will, without any external pressures or threats that force you to commit it.

It’s the hardest to be forgiven if you infringe the free will of others by means of extinguishing their souls, lives, or consciousness.