The sickness the man, who was brought to Jesus, was of three-fold. Firstly, he was possessed by devil, secondly he was blind, and thirdly he was dumb. It was a miserable situation for the man to be in, and hardly any one would help one such man.  But then, there were people in those days, who had compassion on this man, and brought to Jesus, because they knew that Jesus can heal him. This man was brought to Jesus, whom they knew as the Son of David, who could heal him.  When this person was brought to Jesus, he healed this sickman.  When the people saw that this man was healed, they marveled and wondered within themselves, "Is not this the son of David?"  It is at this time that the religious leaders, who thought always to browbeat Jesus on some argument or other, in order to keep their religious superiority, raised their voice against Jesus and accused him of being a sorcerer, who cast out devils in the name of Beelzebub, the great prince of the devils. Jesus knew their crafty thinking about him and, therefore, said to them, if he was casting out devils in the name of Beelzebub, by whose name their children would cast out the devils. He asked this question because during those days there were people, who were casting out devils in the name of Beelzebub. Jesus also made a point there that if a kingdom was divided in itself it would not survive, and if the Prince of Devil, Beelzebub was divided in its kingdom, by casting out devils from within his kingdom, the kingdom gets weakened and the devils' purpose gets defeated. Therefore such an incongruous possibility as was construed by them was foolishness inasmuch as, Jesus said, that unless the strong man of a house was bound, the spoils from his house can not be robbed. 

Jesus came to this world to save sinners, of whom, Apostle Paul, claims himself to be the chief in 1 Timothy 1:15 "This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners; of whom I am chief. If Apostle Paul, who persecuted Christians, when he was known by name, 'Saul', it was because he did all sorts of crimes against Christians, and when he was confronted by Jesus himself, he humbled himself and followed Christ and served him.  We are no better than Apostle Paul and we have also committed sins sufficient enough to grieve Holy Spirit.  According to Bible prophesy, as recorded in Isaiah 42:3 God will not punish any body, who comes to him and confess his/her sins.  He said, "A bruised reed shall he not break, and the smoking flax shall he not quench: he shall bring forth judgment unto truth".  Romans 3:23-24 reads, "For all have sinned, and come short of the glory of God; Being justified freely by his grace through the redemption that is in Christ Jesus".  Jesus was filled with Holy Spirit (Luke 4:1), when Devil confronted him and tempted him. Satan was defeated there and Jesus emerged triumphant from the three rigorous temptations he faced.  Like wise, when we are filled with Holy Spirit we will be victorious over Satan and cunning devices.  Holy Spirit indwells us immediately we are born-again and we need to increase in the knowledge of God and come closer to him as we grow in his knowledge. 

At this time, Jesus very specifically said all manner of sin, even blasphemy against him shall be forgiven of a man, who does blaspheme, but the blaspheme against Holy Spirit shall not be forgiven unto men. There were people, who did blaspheme Jesus when he was being crucified, yet Jesus prayed for them to the Father in heaven to forgive them, but the blaspheme against Holy Spirit can not be forgiven. Adultery, suicide, murder or any other such heinous sin can also be forgiven of a man, but he who refutes the work of Holy Spirit in him, is working against the Holy Spirit. The work of the Holy Spirit is to convict a person of sin, lead him, guide him to the righteous path, and groan in heart while praying to exalt the Father in heaven, and ask for our needs with burden, and pray for others, and also to possess the fruits of the Holy Spirit as described in Galatians 5:22 "...love, joy, peace, longsuffering, gentleness, goodness, faith..."  Although denying the fruit of the spirit is not tantamount to blaspheme against Holy Spirit, the rejection of salvation despite conviction by Holy Spirit is certainly blaspheme.  Jesus meant to say that when a person yields to the conviction of Holy Spirit and accepts Jesus Christ as personal savior, he gets saved and will have eternal life, but when he refuses to the conviction of Holy Spirit and rejects Jesus Christ as his/her personal savior, such sin can not be forgiven of him in this age or in the age to come. Jesus was also saying the miracles done by him were not from devil, as accused by  Pharisees, but they were from heaven above, and through the works of Holy Spirit.  The miracles are done in those days to show the power of God and make it known to the people the love of God that whoever believes in him shall not perish but have eternal life. But unlike what is desired of here, the Pharisees went on to blaspheming the novel works of the Holy Spirit through Jesus were as if they were from the prince of devils, Beelzebub.  Therefore, Jesus was so specific here that those who reject the works of the Holy Spirit and ascribe them to the evil spirits will never be forgiven of their sin, and that is unpardonable sin. Who can give such salvation as Jesus gave us and still offering such great gift to any one who comes to him. We are asked not to grieve Holy Spirit as we read in Ephesians 4:30 "And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption". For all those who commit sins after they are born again, there is chastisement from God so that they can turn back to God and live in righteousness and upright before God. There are those who are convicted every time to repent of their sins and accept Jesus Christ as their personal Savior, but they harden their hearts and reject Jesus.  The Bible calls such rejection of Jesus Christ as their personal savior, in spite of being convicted of their sins, as blaspheme against Holy Spirit.  When such blaspheme happens to reject the conviction of Holy Spirit and reject Jesus as one's personal Savior, the salvation is no where near them.  Such a person as this will not be forgiven of his sins, now in this age nor in the age to come.  This is the unpardonable sin, the blaspheme of Holy Spirit. Finally, never ever dare speak evil about Holy Spirit, nor do belittle the works of Holy Spirit.