How did theologians conclude that blasphemy of the Holy Spirit meant a refusal for repentance?

Matthew 12:22-32 and Mark 3:22-30 both tell the account of the Christ casting out devils while Pharisees accused Him of being possessed by Beelzebub. The Christ rebukes them and declares the following from Matthew 12:31-32: > 31Therefore I tell you, every sin and blasphemy will be forgiven people, but the blasphemy against the Spirit will not be forgiven. 32And whoever speaks a word against the Son of Man will be forgiven, but whoever speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come. It appears that the Christ is telling us that blasphemy against the Father or the Son (i.e. *"God damn it!"* or *"Jesus Jumping Christ!"*) is forgivable, but not of the Holy Spirit. However, most preachers and theologians I have listened to believe that it really means that it means living an unrepentant life. My question is how Christian theologians have made this conclusion and if it holds up to biblical doctrine.