Have I committed unpardonable sin or blasphemy against the Holy Spirit?
Always take the scriptures in context and keep in mind history. This is called the historical-grammatical method of interpretation.
Matthew 12:31-32 (NKJV)
31 “Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men.
32 Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come.
Some people can read this and come away with the understanding that they can be damned for any sin against the Spirit of God. Some would say if you call a miracle by the Holy Spirit as a work of Satan then you have committed the unpardonable sin.
These are not entirely true. We need a complete view or history and Scripture to come to a right understanding of the Matt. 12 passages.
Remember that the work of the Holy Spirit is to testify that Jesus is the savior (John 15:26) and convict the world of sin (John 16:8). Blaspheming the Spirit means rejecting His testimony and conviction that Jesus is the savior. If someone rejects Jesus they are rejecting the only way to be saved and for that reason cannot be forgiven (Acts 4:12).
These are Scribes from Jerusalem whose job is to tell Israel if this is the messiah or not (Mark 3:22). As the people looked to them they pronounced that Jesus was not the savior but did the miracle by the work of Satan not the Holy Spirit. Therefore rejecting the work of the Holy Spirit they rejected Jesus as savior. If someone remains in the sin of rejecting Jesus then there is no hope of salvation for them.
Notice in the Matt 12 passages that Jesus did not say that a person could not repent of this sin just that anyone remaining in the sin could not be forgiven. Even after denying Jesus someone could repent and be forgiven. Look at Peter, he confessed Christ (Matt. 16:16) then denied Him three times (Luke 22:56-62). Jesus allowed Peter to repent and return to Him (Luke 22:32; 62).
You never have to worry if you have committed this sin if you believe that Jesus is Lord and died for your sins.
Pastor Scott Thom