I often get questions about the unpardonable sin and blasphemy against the Holy Ghost as recorded in Matthew 12:31-32 [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. [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.
See All.... This passage has been a problem for many people. I have dealt with a number of people over the years who thought they could not get saved because they had committed this sin. I also found that those who thought they had committed this sin had been guilty of many different things (suicide, abortion, etc.)—all thought by them to be this sin. 

Many good people have seen this passage in different ways. But we must remember that the final authority for truth is always the Bible—not what any man thinks. To understand the passage, we must ask several questions concerning this sin. First, what is the sin of blasphemy against the Holy Ghost? Second, who can commit this sin? Third, what does it mean that this sin can never be forgiven? 

FIRST : What is the sin against the Holy Ghost?

This sin is mentioned in only three places and these are all records of the same incident: Matthew 12:22-33 [22] Then was brought unto him one possessed with a devil, blind, and dumb: and he healed him, insomuch that the blind and dumb both spake and saw. [23] And all the people were amazed, and said, Is not this the son of David? [24] But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils. [25] And Jesus knew their thoughts, and said unto them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand: [26] And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand? [27] And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges. [28] But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you. [29] Or else how can one enter into a strong man's house, and spoil his goods, except he first bind the strong man? and then he will spoil his house. [30] He that is not with me is against me; and he that gathereth not with me scattereth abroad. [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. [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. [33] Either make the tree good, and his fruit good; or else make the tree corrupt, and his fruit corrupt: for the tree is known by his fruit.
See All...; Mark 3:22-30 [22] And the scribes which came down from Jerusalem said, He hath Beelzebub, and by the prince of the devils casteth he out devils. [23] And he called them unto him, and said unto them in parables, How can Satan cast out Satan? [24] And if a kingdom be divided against itself, that kingdom cannot stand. [25] And if a house be divided against itself, that house cannot stand. [26] And if Satan rise up against himself, and be divided, he cannot stand, but hath an end. [27] No man can enter into a strong man's house, and spoil his goods, except he will first bind the strong man; and then he will spoil his house. [28] Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme: [29] But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation. [30] Because they said, He hath an unclean spirit.
See All...; Luke 11:14-20 [14] And he was casting out a devil, and it was dumb. And it came to pass, when the devil was gone out, the dumb spake; and the people wondered. [15] But some of them said, He casteth out devils through Beelzebub the chief of the devils. [16] And others, tempting him, sought of him a sign from heaven. [17] But he, knowing their thoughts, said unto them, Every kingdom divided against itself is brought to desolation; and a house divided against a house falleth. [18] If Satan also be divided against himself, how shall his kingdom stand? because ye say that I cast out devils through Beelzebub. [19] And if I by Beelzebub cast out devils, by whom do your sons cast them out? therefore shall they be your judges. [20] But if I with the finger of God cast out devils, no doubt the kingdom of God is come upon you.
See All... with 12:10
See All.... In each record, Christ casts out devils and is accused by the Pharisees of casting them out by the power of Beelzebub, the prince of the devils (Matthew 12:24But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils.
See All...). In return, Christ gives His warning about blaspheming against the Holy Ghost. In fact, according to Mark 3:30Because they said, He hath an unclean spirit.
See All..., He made His statement about this sin “[b]ecause they said, He hath an unclean spirit”. Jesus was telling them that they had just blasphemed against the Holy Ghost and it would not be forgiven them. 

How did these Pharisees blaspheme the Holy Ghost? They saw Jesus cast out devils by the power of the Spirit of God (Matthew 12:28But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you.
See All...). They knew that it was the work of God. Consider the testimony of Nicodemus in John 3:2The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
See All... where he says: ”...we [Nicodemus was a Pharisee] know that thou art a teacher come from God: for no man can to these miracles that thou doest, except God be with him”.  

The Pharisees did not oppose Jesus because they doubted that He was from God. They opposed Him because they knew He would take their position from them (see John 11:47-48 [47] Then gathered the chief priests and the Pharisees a council, and said, What do we? for this man doeth many miracles. [48] If we let him thus alone, all men will believe on him: and the Romans shall come and take away both our place and nation.
See All...). It is with this clear knowledge of who Christ was that they attributed His works to the devil. That is the sin of blasphemy against the Holy Ghost—to knowingly attribute the miracles of Jesus Christ, which were done by the Holy Ghost, to the devil. 

SECOND: Who can commit this sin?

This sin can only be committed by someone who has seen the work of Jesus, known it was done by the power of God’s Spirit and yet attributes it to the devil for personal gain or hatred. I personally believe that this sin could only be committed when Jesus was present on the earth. This would explain why the sin is never mentioned again in the New Testament.

But even if it could be committed today, it could not be committed by a true believer in Christ. If someone truly believes in Jesus, he will not knowingly accuse Jesus of doing His work by the power of the devil. The very act of saying such a thing would be proof that He did not know Jesus as his Lord and Saviour (see 1John 2:19They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us.
See All...; 4:1-3
See All...; 2John 9). No, only a lost person could commit this sin. 

THIRD: What happens when a person commits this sin?

Well, when a man blasphemed against the Holy Ghost, he sinned against the very one who must deal with him and draw him to salvation. The Holy Ghost reproves us of sin (John 16:7-11 [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. [8] And when he is come, he will reprove the world of sin, and of righteousness, and of judgment: [9] Of sin, because they believe not on me; [10] Of righteousness, because I go to my Father, and ye see me no more; [11] Of judgment, because the prince of this world is judged.
See All...) and draws us to God. If He does not do His work, we cannot be saved (John 6:44No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day.
See All...). This man’s sin is never forgiven because He has cut off the very one who must draw him to be saved. Without this drawing, he will never be saved.  

This is actually another proof that this sin only operated during the earthly ministry of Jesus Christ. Christ has promised to draw all men to Himself through His crucifixion on the cross (John 12:32And I, if I be lifted up from the earth, will draw all men unto me.
See All...). Evidently then, this sin could only be committed before Christ was crucified. Today, there is no group of people who are not drawn (at least at some point in their lives) to Christ. 

Since a man who has not been drawn by the Holy Ghost has never been saved, blasphemy against the Holy Ghost cannot cause the losing of one’s salvation. But consider this. If you or anyone else had committed this sin, you would never again be convicted by the Spirit of your need for a Saviour or of your need to get right with God.  

The very fact that you are concerned is proof that the Holy Ghost is still working with you and that you have not blasphemed the Holy Ghost. Do not let the devil use false teaching on this doctrine destroy your peace or make you think you cannot be saved. The call to salvation still proclaims, “Whosoever will, let him take of the water of life freely” (Revelation 22:17And the Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely.
See All...).