What is the meaning of Matt. 12:31-32 where it says blasphemies against the Holy Spirit will not be forgiven? Aren’t all sins forgiven when one repents?
Yes, all sins are forgivable provided we accept the grace of the Holy Spirit that makes it possible for us to repent and seek forgiveness. Deliberately refusing the grace of repentance is the “unforgivable sin” because we are, essentially, refusing forgiveness itself. Here is the explanation of the Catechism of the Catholic Church:
“Therefore I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven.” There are no limits to the mercy of God, but anyone who deliberately refuses to accept his mercy by repenting, rejects the forgiveness of his sins and the salvation offered by the Holy Spirit. Such hardness of heart can lead to final impenitence and eternal loss (CCC 1864).