Blasphemy against the Holy Spirit

Matthew
Matthew 12:31 and 32 says "And so I tell you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven.  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."

This passage was always a bit confusing to me, and I wondered what exactly was meant by speaking against the Holy Spirit.  Since I am now writing this blog, I took the time to look into these verses from today's reading.  What I found made a lot of sense.  I looked at some online commentaries from the bible.cc website (mainly Barnes' notes on the bible).  When Jesus was talking about the Son of Man, he referred to his earthly nature.  Insults or comments against that part of himself could be forgiven, such as comments regarding his birthplace (nothing good ever comes from Nazareth).  Speaking against the Holy Spirit referred to Jesus' divine nature, the part of him that was 100% God.  For people to speak negatively about that, such as by assuming he came from the devil rather than God, there would be no excuse.
Wesley describes the blasphemy of the Holy Spirit as follows: "It is neither more nor less than the ascribing those miracles to the power of the devil, which Christ wrought by the power of the Holy Ghost."  Barnes puts it this way: "He that speaks against me as a man of Nazareth - that speaks contemptuously of my humble birth, etc., may be pardoned; but he that reproaches my divine nature, charging me with being in league with Satan, and blaspheming the power of God manifestly displayed "by me," can never obtain forgiveness."