Unforgivable sin

In Christian hamartiology, eternal sins, unforgivable sins, or unpardonable sins are sins which will not be forgiven by God. One eternal or unforgivable sin is specified in several passages of the synoptic gospels. Mark 3:28-29, Matthew 12:31-32, and Luke 12:10 state that there is one sin considered eternal and that is "blasphemy against the Holy Spirit".

Roman Catholicism states that there are six sins that blaspheme against the Holy Spirit. They are despair (believing that one's evil is beyond God's forgiveness), presumption (glory without merit), envying the goodness of another (hating a good person for his goodness), obstinacy in sin (clinging to a sin and refusing to think that the sin does not do much good), final impenitence (purposedly avoiding the repentance of a sin), and deliberate resistance to the known truth (denying reality, especially fully known parts of the faith, and this includes misrepresenting parts or all of the Christian faith to make it seem undesirable).

Several passages in the Bible are frequently interpreted as referring to the unforgivable sin:

According to the Catechism of the Catholic Church §1864, 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.

Thomas Aquinas lists, or has responded to, six sins that supposedly go against the Holy Spirit:

...
Wikipedia