A man blasphemes the Holy Ghost. As soon as he does it, he regrets it and tries to repent, but, of course, there is no forgiveness for those who blaspheme the Holy Ghost. The man spends his day in dread and fear. That night, he looks out his window and sees Satan and a legion of demons racing down the street toward him. He screams and tries to get away. He jumps in his car and speeds over to the church, but as he runs from his car to the church, he collapses and dies right on the doorstep of the church.
This story has several variations. Sometimes it is a group of men (two or three) who blaspheme the Holy Ghost together and all die that same day. The details of the manner of death differ--the blasphemers are said to be hit by cars, die of heart attacks, or simply drop dead for no apparent reason.
This is one of those stories that is intended to frighten people into compliance. Blaspheming the Holy Ghost is often interpreted by Pentecostals as declaring something not of God when it is of God. So, in other words, according to Pentecostal beliefs, if someone sees an "outpouring of the Holy Ghost " with people speaking in tongues and jumping and shouting, and they say, "I don't think God is pleased with this", then they may be blaspheming the Holy Ghost, and they may be dead within 24 hours with hordes of demons feasting upon their souls.
Of course, this makes Pentecostals very afraid to question whether something is "of God", because they may be risking not only their life but also their eternal soul, to do so.
But this is absolute nonsense. For one thing, I have been questioning the authenticity of these "outpouring" for . . . let's see . . . fourteen years now. And I have seen no hordes of demons. And, although I am certain I will die someday, as everybody does, it certainly did not immediately follow my questioning Pentecostal practices.
But more to the point, the Bible encourages us to use discernment and to search the scriptures to see whether things are 'of God'. Paul even says in Galatians 1 that even if an angel appears and preaches something, we still are to carefully evaluate it and reject it if it is not Biblical.