For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
Despising the Spirit of grace to help us not to sin, is sinning against the Spirit of grace despitefully.
If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it.
Sinning unto death is rejecting the convicting draw of the Spirit unto the grave, and so is sinning against His spiritual grace unto death.
That is why we don't pray for the unrepentant, because if they are refusing to hear God, then what help is prayer to God for them?
But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils.
Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.
And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.
The blasphemy against the Holy Ghost is making His work that of the devil.
Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.
And when he is come, he will reprove the world of sin, and of righteousness, and of judgment.
The work of the Spirit upon all flesh today is to convict all men of sinning. And so, any man that says conviction for sinning is hateful and of the devil, is blaspheming the Holy Ghost.
But he that sinneth against me wrongeth his own soul: all they that hate me love death.
Conclusion, the work of the Spirit is to convict, forgive, and give new birth with eternal life, and so anyone refusing to repent of sinning, is sinning against the Spirit and his own soul.