Having been born into Christ's Kingdom, our goal is to not sin. "My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate [intercessor] with the Father, Jesus Christ the righteous" (1 John 2:1,2 KJV). "And people who stay one in their hearts with him won't keep on sinning. If they do keep on sinning, they don't know Christ, and they have never seen him" (1 John 3:6, CEV).
FORGIVENESS OF SINS IS CONDITIONAL
Notice that a Christian's sins are forgivable but conditional upon our acknowledging them, repenting [i.e., "do not keep sinning"], and confessing them. A Christian, like the child of God, King David, in the Old Testament, can be forgiven anything because of God's grace:
"Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works, Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered. Blessed is the man to whom the Lord will not impute sin" (Romans 4:6-8, KJV).
This passage points out that God's grace forgives unrighteous works (e.g., David's murdering Uriah and his adultery with Bathsheba). Going to the passage quoted from David (Psalm 32) we see that David had to do God's works in order to get this forgiveness from God's grace. For example, he writes, "I acknowledged my sin unto thee, and mine iniquity have I not hid. I said, I will confess my transgressions unto the Lord; and thou forgavest the iniquity of my sin" (Psalm 32:5).
A necessary inference in confession of sin is that repentance accompanies this confession. Jesus told the woman caught in adultery "I don't condemn thee; go and sin no more" (John 8:11). Repentance is a change of mind produced by godly sorrow toward a change of action: "godly sorrow worketh repentance [Greek: "reversal" Strong's]" (2 Corinthians 7:10). David's confession came as a result of godly misery: "For day and night thy hand was heavy upon me: I became thoroughly miserable while a thorn was fastened in me" (Psalm 32:4, Brenton).
Some say that the only unforgivable sin are the sins referred to in Hebrews 6:4-6; to wit, unrepented sins. "For it is impossible... If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put himto an open shame". Hence, the argument is, "the unforgivable sin" is the one that one does not repent of.
However, if a sin can be forgiven (via repentance and confession) then that is not an unforgivable sin. It is forgivable through repentance and confession. Unforgiven is not the same as unforgivable.
THE UNFORGIVABLE SIN
The unforgivable sin is "blasphemy against the Holy Spirit." This is the only sin that is characterized as unforgivable.
What is this "sin unto death"? John doesn't elaborate but we know that the only sin mentioned of that nature is what Jesus identified as the "blasphemy against the Holy Spirit." What is the "blasphemy against the Holy Spirit"?
The word "blaspheme" is used in its different forms about 59 times in the New Testament. Among the translations "blaspheme" in 1 Corinthians 5:11 is defined as "railer", "abusive", "curses others", "reviler" , "abuses others with insults", and "slanderer". Christians that are guilty of "blaspheming" are to be disciplined so that they might "be saved" (verse 5) and to keep the congregation pure (v. 8). So blasphemy itself is not unforgiveable because the guilty one can be saved by discipline.
Jesus said any blasphemy would be forgiven, and we know that Jesus was blasphemed at the crucifixion but He prayed for His blasphemers: "Forgive them, Father, for they know not what they do" (Matthew 27:39; Luke 23:34). If Jesus prayed for His blasphemers, then that was not a sin unto death (1 John 5:16). In addition He prayed for sinners who yet were unrepentant. Unrepentant sins is not a sin unto death.
BLASPHEMY is literally to "speak to hurt." --G988 ¯mia Thayer: slander, detraction, speech injurious, to another's good name; impious and reproachful speech injurious to divine majesty [bláptein to harm) + -phemos speaking, derivative of ph?me speech]*. To blaspheme the Holy Spirit is to speak to harm the Holy Spirit.
BECAUSE THEY SAID
Let’s put it into the context. Jesus was talking specifically to ones who had seen his miracle of completely healing a blind and mute demon-possessed man (Matthew 12:22). Rather than acknowledge that Jesus had used divine powers, they attributed his power to Satan (v. 24).
Mark 3:30 states, "Because they said, He hath an unclean spirit." Hence, to vilify the Spirit of God is to be "guilty of an eternal sin" (ASV). There's a discussion about when it can be committed; just before the cross or after the cross, both, or was it limited to the first century. Evangelists Winkler and Nichols conclude that Jesus was saying that there was no forgiveness in either the Jewish age or the Christian age.** The expression is similar to an oft repeated phrase, "for ever and ever" (e.g., Revelation 20:7).
The passages are very clear that to blaspheme the Holy Spirit at any time will never be forgiven; i.e., forever and ever. It has been pointed out that no one has been given the right to sin, whether to hurt man or God's Spirit. Forgivable sins are to be washed away by the blood of Christ in the act of baptism by intitial believers (Romans 6:4; Acts 22:16) and confession of sins by penitent believers (1 John 1:7f) as they purposely "walk in God's Light". But to speak to hurt the Holy Spirit is unforgivable.