The Bible tells us (I can't find the verse right now) that the only unforgivable sin is to blaspheme the Holy Spirit. I have never really heard an explination as to what this entails. Could you help?Well, first of all, here is the verse in question:
28 "Truly, I say to you, all sins will be forgiven the sons of men, and whatever blasphemies they utter;
29 but whoever blasphemes against the Holy Spirit never has forgiveness, but is guilty of an eternal sin" --
30 for they had said, "He has an unclean spirit."
Now, theologians identify six sins as being "against the Holy Spirit." They are:
3. final impenitence
4. obstinacy in sin
5. resisting the known truth
6. envy of another's spiritual welfare.
Final impenitence is the only one among them that is unforgiveable in the absolute sense. This is because final impenitence means dying without remorse for the sin you have committed. With your very last breath you can pray for forgiveness. But, if you waste those precious seconds, if you persist in sin to the very end, then there is no longer any hope for forgiveness. Even Purgatory only cleanses us of the temporal punishment due to sin and our various attachments to sin.
All the other sins are "unforgiveable" insofar as they lead a person towards final impenitence. Despair can cause us to think to ourselves, "God won't forgive me" or "God can't forgive me." This, of course, leads us to reject the forgiveness of the Spirit because it would all be "pointless" or "meaningless" or "ineffective" if God didn't care. Presumption leads to impenitence because it causes us to assume that we are in right relationship with the Lord and thus do not need forgivness, when we really do. Obstinancy in sin certainly leads us down the road of final impenitence because it is a stubborn refusal to turn away from sin and seek forgiveness. Resisting the known truth would lead to unforgivness because it consists of a person denying that the Holy Spirit forgives sin through the Sacrament of Penance or through a prayer made in perfect contrition. Why repent if the Spirit does not actually work through our instruments for repentance? Finally, envy does this by causing us to reject the Spirit because we are bitter that another person has been blessed so abundantly and we seemingly have not. This would thus cause contempt towards the Spirit for not blessing us as equally as our neighbor.
The Pocket Catholic Dictionary summarizes this rather nicely:
SINS AGAINST THE HOLY SPIRIT. Major offenses that carry a stubborn resistance to the inspirations of the Holy Spirit and a contempt of his gifts. They are despair of one's salvation, envy of another's spiritual good, opposing known truths of faith, obstinacy in sin, presumption of God's mercy, and final impenitence. Because those who sin in this way, resisting grace, do not wish to repent, we say that their sins cannot be forgiven them.The Navarre Bible Commentary is also very helpful:
28-30. Jesus has just worked a miracle but the scribes refuse to recognize it "for they had said `He has an unclean spirit'" (verse 30). They do not want to admit that God is the author of the miracle. In this attitude lies the special gravity of blasphemy against the Holy Spirit--attributing to the prince of evil, to Satan, the good works performed by God Himself. Anyone acting in this way will become like the sick person who has so lost confidence in the doctor that he rejects him as if an enemy and regards as poison the medicine that can save his life. That is why our Lord says that he who blasphemes against the Holy Spirit will not forgiven: not because God cannot forgive all sins, but because that person, in his blindness towards God, rejects Jesus Christ, His teaching and His miracles, and despises the graces of the Holy Spirit as if they were designed to trap him (cf. "St. Pius V Catechism", II, 5, 19; St. Thomas Aquinas, "Summa theologiae", II-II, q. 14, a. 3).For more on sinning against the Holy Spirit, see Section VIII "Sins Against the Holy Ghost" in the New Advent article on the Holy Ghost.