The Unforgivable Sin

There are several candidates for this but it is not a simple subject.

Firstly, we must remember that all sin is not a physical act but an attitude, i.e. an act of the mind. This is very clear from

Mat 5:28  But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart. 

Therefore, the Unforgiveable Sin must also be an Attitude, not the act(s) arising therefrom but each of the texts giving the awareness of the possibility of an Unforgivable Sin seems to refer to the act arising.

Mat 12:31  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. 

Mat 12:32  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. 

which is repeated in Mark 3: 28.29 and Luke 12:10.

However, Mat 5.18 still applies 

Mat 15:18  But those things which proceed out of the mouth come forth from the heart; and they defile the man. 

Mat 15:19  For out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies: 

and

Mar 7:21  For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, 

Mar 7:22  Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: 

Mar 7:23  All these evil things come from within, and defile the man

Therefore the Unforgivable sin originates in the heart (emotionally not clinically).  

Consider

1Jn 5:16  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. 

In the Old Testament there is only one commandment which appears to carry the unforgiveable warning.

Exo 20:7  Thou shalt not take the name of the LORD thy God in vain; for the LORD will not hold him guiltless that taketh his name in vain. 

Remember, our eternal security relies (and did so in the Old Testament as well) not on us achieving righteousness but solely on God holding us guiltless - on the grounds of Jesus' sacrifice - so this aspect of the Unforgiveable Sin cannot be committed by true Christians - the Holy Spirit will protect.

Therefore, it seems that to commit the unforgivable sin there must be a definite intention to carry out the act (whatever it may be). It cannot be committed accidentally. The emphasis in scripture is that it is "against the Holy Spirit", not against Jesus. Note that there is no reference to God as "The Father" in the warnings.  It is possible that the emphasis on the Holy Spirit is because each personality of the Trinity has a specific involvement with mankind and the Holy Spirit carries out the conviction of sin, the teaching of believers and the protection of the believer's eternal security.

Joh 16:7  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. 

Joh 16:8  And when he is come, he will reprove the world of sin, and of righteousness, and of judgment: 

Joh 16:13  Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. 

Eph 4:30  And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption. 

BUT   

While Jesus walked the Earth, He was God's representative to and communicant with, mankind. After His ascension, that role has been ascribed to the Holy Spirit.

Joh 1:18  No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him. 

Gen 6:3  And the LORD said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years. 

Joh_14:16  And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;

Joh_14:26  But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.

Joh_15:26  But when the Comforter is come, whom I will send unto you from the Father, even the Spirit of truth, which proceedeth from the Father, he shall testify of me:

Joh_16:7  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.

Therefore, usually (but there may be exceptions as all righteous things are possible for God) the Holy Spirit is the sole channel of communication with mankind (until, possibly, the Last Days) so the Blasphemy is something which cuts our communication with God. There are two other warnings to believers regarding the Holy Spirit.

Eph 4:30  And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption.  

This follows an exhortation for believers to refrain from several inappropriate actions and does not indicate the withdrawal of the Holy Spirit from a believer, so cannot constitute the Unforgivable Sin.

1Th 5:19  Quench not the Spirit.  

The Greek word for "Quench" means "Extinguish". but "Spirit" here is not coupled with "Holy" and is the same as in

Mat 5:3  Blessed are the poor in spirit: for theirs is the kingdom of heaven. 

where it clearly means emotional strength or determination. Again,    Quench not the Spirit.   is not a candidate for the Unforgivable Sin.

Therefore, the Unforgivable Sin must be some deliberate act by a person who is not a Bible believing Christian which prevents the Holy Spirit from fulfilling one or more of His purposes with regards to that person. Of the three such purposes mentioned above, the only one which can possibly be involved is that of convicting sinners of their sinfulness. The clearest acts of blasphemy in the old testament are those of idolatry, i.e. attributing God's power to other things or beings. Therefore, it seems that it is possible for an unbeliever to deliberately and consciously. attribute the actions of the Holy Spirit to a totally unacceptable source and that could only happen when the Holy Spirit was actually dealing with that person. 

Another clue to the meaning of blasphemy is

Mat 26:64  Jesus saith unto him, Thou hast said: nevertheless I say unto you, Hereafter shall ye see the Son of man sitting on the right hand of power, and coming in the clouds of heaven. 

Mat 26:65  Then the high priest rent his clothes, saying, He hath spoken blasphemy; what further need have we of witnesses? behold, now ye have heard his blasphemy. 

This indicates that claiming to be God (by a sinful man) is an act of blasphemy. Could the unforgivable sin be the act of claiming to perform the work of the Holy Spirit? This would happen if someone who is not a true Christian claims to be a teacher (a function of the Holy Spirit) but then teaches heresy.

Perhaps the clearest clue is the separation of blasphemy against the Holy Spirit from that against the Son and the Father.  The work on earth reserved solely to the Holy Spirit is that of "The Comforter" (replacing the loss of Jesus in that roll). The Holy Spirit is clearly the current representative on Earth of Jesus.  Any other being claiming to be Jesu's earthly representative is directly denying the function of the Holy Spirit, thus blaspheming Him.  Over the centuries  there have been many falsely claiming such a function but the obvious, regular candidate is the Bishop of Rome,  i.e. the Pope.  It seems incredible, but that is clearly what the Bible teaches.  Scripturally, the Pope, unless he personally revokes such a claim, is one of the few people totally denied the possibility of eternal life with God!  The official position of the Roman Catholic church is that their tradition is superior to the Scriptures. No truly Bible believing Christian can accept that.

Joh 14:26  But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.

Joh 16:7  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. 

Joh 16:8  And when he is come, he will reprove the world of sin, and of righteousness, and of judgment: 

Joh 16:9  Of sin, because they believe not on me; 

Joh 16:10  Of righteousness, because I go to my Father, and ye see me no more; 

Joh 16:11  Of judgment, because the prince of this world is judged. 

Therefore, the unrepented denial of the Holy Spirit's ministrations as detailed in Joh 16:8, clearly can be described as "blasphemy". thus falling into the "unforgiveable" category.  Whilst the doctrine of The Trinity (One God having 3 equally godly characteristics) is clearly taught in the Scriptures, the separate aspects of Father, Son and Holy Spirit are also taught, as each aspect is  attributed with a clearly defined function and it is thus possible to blaspheme against an aspect individually.