"And whenever you stand praying, forgive, if you have anything against anyone, so that your Father also who is in heaven may forgive you your trespasses.” (Mark 11:25)
Based on interactions with a person whose state of being is a rigid, maladaptive self-concept in which self is the reference point for all things, and others are only accessories, I'm inclined to think that an unforgivable sin might reside within that state of being. A rigid, maladaptive god unto oneself, demanding worship from others. A person in this state leaves a wide path of inestimable devastation through various forms of abuse, and in fact resembles Satan's persona, whose eternal commitment is to be 'as God' and 'be worshipped'.
I can't say for sure whether the forgiveness of God is possible for the rigid, maladaptive persona. What I can say is that individuals whose lives have been devastated by such a persona, forgiveness toward them is possible. Simply let them float away into the wide world knowing that except for the Grace of God, there go I and that in Christ, all the devastating damage will be used for God's glory and your own good. Not easy, possible.
My dear ones, God will do what God will do with others, you go toward Christ with flexible and adaptable personas, in love toward God in Christ. Life-devastating damage can be endured and used in God's capable hands. In the aftermath of devastation, abundant life comes as we work toward 'hallelujahs of redemption' that drown out the cries of pain, regardless of who or how pain was inflicted or whether this persona is 'unforgivable' or not.
Christ endured passively for the forgiveness of our active disobedience. Christ obeyed actively for the application of His righteous due to our passive obedience. Any persons by whom we are devastated cannot become more than they are if we are less than we should be in Christ. They may or may not become more than they are anyway, but at least we will not have become less than we are called to be in Christ.
