Hebrews 3:13 But exhort one another every day, as long as it is called "today," so that none of you may be hardened by the deceitfulness of sin. (NRSV)

This word ‘hardened’ should scare every Christian, but most are not afraid of being hardened. Most are afraid that they or their loved ones will become drunkards. Better to be a drunkard than hardened. There is more chance for one gripped by one specific sin, who still has a heart and conscience, to repent than for the hardened, who commits no vulgar sin condemned in the age in which he lives. You can not find a person who is hardened in the sense of this chapter, who does not have a working knowledge of terms of the gospel of Christ. Remember the publican and the sinner. If we are not startled by the word ‘hardened’, if it produces no shame or fear, if we are not already wondering what the danger is then we have already begun to become hardened.

No child is born hard they grow up and become that way. Matthew 18:3 and said, unless you change and become like children, you will never enter the kingdom of heaven. (NRSV)

Hardening starts when we begin to fight against tenderness, then we silence conscience as being inconvenient to our success, and finally we question the reality of things unseen.

Remember when you would weep over a dead bird, now you don’t weep over lost souls!
Remember when you would blush at sin, today there is no blush and no inward shame.
Remember when we believed in God, now your hardly sure of anything.
It is the inevitable result of the stifling of tears and the refusal to listen to conscience that Faith dies.
The time comes when the boy who wept hearing of the death of Jesus but as a man, hears it with no emotion at all.
Beware when a man still listens to the ways of God but never trembles as he departs from them.
The most difficult to reach with the gospel are those who know it well and yet are unmoved by it.

How do you become hardened? Mentally agreeing with the word and yet not answering its claims; that is the sin which hardens. Being complacent and following your heart instead of the scriptures. Stay in the scriptures and you will stay in his ways, but since his ways are not ours and the heart is desperately wicked, if you quit meditating on the scriptures you will end up following your heart. And therefore start becoming hardened.

When he disobeys he becomes hardened by the very truth that could have softened him and he becomes enslaved and debased by the very message that might have made him free indeed. Why would he hear and understand yet not obey?

The son alone can make you free but if you have refused to obey the truth and so been guilty of disbelief it’s because you allowed yourself to be deceived by sin’s promise of freedom, while all the time it has been forging your chain and you are being hardened!

1 Peter 2:18-21 Sin deceives you into thinking you find liberty elsewhere. Corrupt men have used Christianity to enslave, but true Christianity always sets men free. The concept that you must get outside the call/will of God to be free is nothing but a lie!

The Unpardonable Sin - those who said "no man can do what Jesus did except God be with him.", are the very same who attributed Jesus miracles to Beelzebub. Jesus then said blasphemy of the Holy Spirit will never be forgiven. The unpardonable sin occurs when you receive the Gospel, and through the Holy Spirit gain the absolute knowledge that Jesus is God and savior then "you trod under foot the Son of God, and count the blood of the covenant, wherewith you were sanctified, an unholy thing, and do despite unto the Spirit of grace. See Hebrews 10:10,26-31 Fully understanding the gospel and rejecting it will never be forgiven.

John 6:44 says no man comes to Christ without God’s spirit drawing him. In Romans 1:22-32 makes it clear, When we worship the creature (self) rather than creator God begins to give us up to a reprobate mind. In Genesis 6:3 Gods spirit will not always strive with man. Ephesians 4:30 the Holy Spirit can be grieved away. In 1 John 5:16 there is a Sin unto death. In 2 Thessalonians 2:10-12 God sends a strong delusion so we believe the lie and are damned.

If you commit the Unpardonable Sin the Holy Spirit will leave you and you will no longer believe. See 1 Corinthians 15:2. IF you still believe and want to be saved, then you couldn’t have committed it!