“No one who blasphemes against the Holy Spirit will be forgiven.”
Jesus speaks of blaspheming against the Holy Spirit as the unforgivable sin immediately after the scribes and Pharisees had attributed his miracles to the work of the devil instead of to God.
A sin can only be unforgivable if repentance (admitting wrongdoing and asking forgiveness) is impossible. There are no limits to the mercy of God, but we can reject his mercy by refusing to ask God’s pardon for our wrongdoing and by refusing to accept the help he gives us to turn away from sin and from whatever would keep us from doing his will.
God gives sufficient grace (his favor and mercy towards us) and he gives sufficient help (his wisdom and strength) to all who humbly call upon him. Giving up on God and refusing to turn away from sin and disbelief results from our own sinful pride, stubborn will, and the loss of hope in God’s promises.God never turns a deaf ear to those who seek his help and listen to his voice – his word of hope, pardon, and freedom from sin and oppression. (Don Schwager)