To blaspheme means to misuse or maliciously slander God’s name. The third commandment instructs us not to misuse God’s name and says He will not hold anyone guiltless who does (Exodus 20:7). The Bible also uses the word blasphemy to describe someone who ‘sins defiantly’ (Numbers 15:30) or who sets up another god and worships it (Ezekiel 20:27-28). It is this crime that the Pharisees accuse Jesus of when He declares Himself to be God by claiming to forgive sins (Matthew 9:3). Jesus says that it is actually blasphemy to deny that either He or the Holy Spirit is God (Matthew 12:30-32). Jesus says here that to maliciously slander, or blaspheme, what is obviously the work of the Holy Spirit, by saying that it is actually the work of Satan, is unforgivable.
