Look at the 3rd of the 10 Statments Yah scribed in stone.
You shall not lift up, support, or advance, forgive or dignify, respect or tolerate, through the name or reputation of Yahuweh your God, accordingly, lifeless and worthless deception or devastating and destructive falsehood, for indeed Yahuweh will not forgive or leave unpunished those who relationally deceive, beguile, or delude, using clever trickery to mislead in association with His name to promote vain and ineffectual lies which lead to lifelessness and destruction or devastating deceptions which nullify our existence leading to emptiness.
You shall not tolerate (nasa - lift up, accept, advance, bear, respect, regard, yield to, or pardon) the name (shem - position, individual nature, designation, honor, authority, character, mark, fame, prominence, reputation, or report) of YHWH (Yahuweh) your God (elohiym - Supreme and Mighty One, Deity) in a desolate (shaw - separating, abandoning, forsaking, damning, deserting, lifeless, debilitating, wretched, destructive, evil, beguiling, false, ruinous, idolatrous, harmful, devastating, deceptive, or ravaging) way. For Yahuweh will not exonerate (naqah - cleanse, acquit, hold blameless, leave unpunished, or forgive) him who accepts (nasa - lifts up, tolerates, advances, respects, yields to, or pardons) His authority (shem - position, nature, designation, honor, name, character, mark, prominence, reputation, and report) being used in damning (shaw - desolating, separating, abandoning, forsaking, lifeless, beguiling, false, or deceptive)way.
Exodus chapter 20.
Bending and twisting Yah's word is lifting up and supporting lifeless deceptions, and is the one thing Yah said He will not forgive.
The reason, or one of the reasons, this is unforgivable is that it is the spiritual equivalent of murdering someone. Choosing to reject Yah your self is one thing, but knowingly and willfully leading others away is the equivalent of destroying their souls.