The unpardonable sin is otherwise known as the blasphemy of the Spirit. It is specifically mentioned in the parallel passages of Matthew 12:30-32, Mark 3:28-30, and Luke 12:10. It is conspicuously absent from the book of Acts and the Epistles, which strongly suggests the limited time frame in which this particular sin could be committed. Jesus Himself is the originator of the unpardonable sin. Before singling out the great danger of committing the blasphemy of the Spirit directed toward some Pharisees who attributed His powers of exorcism to Satanic activity, Jesus takes great pains to describe the height, length, width, and depth of His forgiveness toward any and every other sin (Matt 12:38-40; Mark 3:28-30). The unpardonable sin is therefore a singular and extraordinary category of unbelief that is anchored in the Gospel period when the historical Jesus walked the earth. It cannot be committed today. Dr. Lewis Sperry Chafer sharply writes, “When considering the subject of the blasphemy of the Spirit, it may well be noted that, quite beyond human explanation, men do not swear in the name of the Third Person. From this fact, it may be concluded that there is now and ever has been a peculiar sanctity belonging to the Holy Spirit. His very name and title implies this.”