The Unpardonable Sin ...

something so grave that it will not be forgiven, either in the present age or in the next one, even though God is normally eager to forgive. 

Matthew 12:31-32 (kjv)
31  Wherefore I say unto you, All manner of sin and blasphemy shall be forgiven unto men: but the blasphemy against the Holy Ghost shall not be forgiven unto men.
32  And whosoever speaketh a word against the Son of man, it shall be forgiven him: but whosoever speaketh against the Holy Ghost, it shall not be forgiven him, neither in this world, neither in the world to come.

So what about blasphemy against the Holy Spirit is unforgivable? For me to even begin to answer this, you need to understand what the Holy Spirit does. Then you will be able to see why blasphemy against Him is so serious a sin that it cannot be forgiven, neither in this life nor in the next.

The Holy Spirit does three things:

[John 14:26] He teaches us the things we need to know for our salvation.

[John 16:13] He guides us into all truth.

[John 16:7-8] His mission is to convict of sin.

As long as we allow Holy Spirit to teach us, guide us, and convict us: we could never commit the unpardonable sin.  If, however, we refuse to acknowledge these three areas of ministry of Holy Spirit: that is when people begin to step closer to the deadly parameters of the worst sin there is.

If you constantly resist the draw of the Holy Spirit until you don't hear His voice anymore; that is Blasphemy against the Holy Spirit. Your conscience is seared (1 Timothy 4:2). This is also called 'grieving away' the Holy Spirit. Ephesians 4:30 And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption. Eventually, you lose the capacity to repent. If you cannot repent, you cannot be forgiven, because you have rejected the Spirit that convicts of sin [John 16:8].

If you still feel conviction and have a desire to repent of sin, then you have probably not committed the unpardonable sin.

Maranatha,
Anna