“…’ whoever speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come’ (Matt. 12:31-32). This refers to absolute faithlessness, deliberate blasphemy, stubborn opposition to God, Satanism, and inability to repent. In such a state, a person’s nature changes, making him a demon in the flesh. This commandment exists not because God is too strict, but simply because a person’s repentance in this altered state is impossible.”
(Catalog of Good Deeds of St Elisabeth Convent)