Though this is a very sad and troubling thing, it is ironic that their challenge is grounded in a somewhat errant view of the “unforgivable sin” which is spoken of Matthew 12:32 and Mark 3:29. Though Jesus does teach that blasphemy of the Holy Spirit is an unforgivable sin, we mustn’t forget that in Mark 3:28 Jesus also said “I tell you the truth, all the sins and blasphemies of men will be forgiven them.” The reality is that sin that is repented of is sin that is forgiven. So what is this unforgivable sin? John Piper defines it as:
The unforgivable sin of blasphemy against the Holy Spirit is an act of resistance which belittles the Holy Spirit so grievously that he withdraws for ever with his convicting power so that we are never able to repent and be forgiven.Another way of looking at it is that the severity of a blasphemy is not for us to decide. It is ultimately between the individual and God. If one makes a statement of rejection and later repents of their statement, they are clearly not guilty of this unpardonable sin.
For an exposition on this issue of the unforgivable sin you can read this message given by John Piper in 1984. In the mean time, we should pray for these individuals who are lashing out in this way. This situation should also remind and motivate us to continue to share the love of Jesus Christ with this lost and hurting world in which we live.