What is Blasphemy against the Holy Spirit?
Matt 12:32 says "Anyone who speaks a word against the Son of Man will
be forgiven, but anyone who speaks against the Holy Spirit will not be
forgiven, either in this age or in the age to come."
The blasphemy against the Holy Spirit is deliberate rejection of Christ
and His salvation. It is the ultimate sin that by its very
nature puts a man beyond the opportunity of salvation. This is
because it is the Holy Spirit who brings the offer of salvation to the heart of
man. Salvation is granted only upon a positive response to
the His prompting. To reject Him is to act presumptuously and thus to
blaspheme God. Those who reject His offer of salvation are in
reality blaspheming the very nature of God Himself and the genuineness of His grace.
Owen Weber 2009