The only unforgivable sin

In today's Gospel reading at Mass, we hear Jesus proclaim the following words which may seem difficult and troubling to grasp: "Everyone who says a word against the Son of man will be forgiven, but no one who blasphemes against the Holy Spirit will be forgiven" (Lk 12:10). So, what does it mean to sin or blaspheme against the Holy Spirit?

Blaspheming against the Holy Spirit can be understood as hardness of heart. It means that a person doesn't seek the forgiveness and mercy of God through the Holy Spirit either because he (or she) doesn't think he has anything to confess to God or because he doesn't think God can forgive him (for a particular sin). Whatever the reason, he "deliberately refuses to accept God's (infinite) mercy by repenting, rejects the forgiveness of his sins and the salvation offered by the Holy Spirit" (Catechism of the Catholic Church, # 1864).

If a person lives his whole life rejecting the forgiveness of God through the Holy Spirit, "such hardness of heart can lead to final impenitence and eternal loss" (CCC, # 1864). However, as with any sin, if he repents of his hardness of heart at any moment before death, he can be forgiven. At that point, his heart is finally open to the forgiveness of the Spirit. God's mercy knows no limits with a contrite heart; the only heart that God can't touch (and thus forgive) is the one that isn't open to His forgiveness.

The only unforgivable sin, then, is the one that is intentionally not confessed. It is a sin against the Holy Spirit because it is the Spirit that forgives any and all sins (see Jn 20:20-23). The Spirit can forgive any and all sins that are confessed with a contrite heart until the moment of death. Anyone who seeks Christ's forgiveness acknowledges the power of His Spirit to forgive, and is forgiven. Anyone who does not ask Christ to be forgiven denies the power of His Spirit, and is not forgiven.