The only unpardonable sin is rejecting the "Gift of God". Jesus.
Ephesians 2:4 But God, who is rich in mercy, because of His great love with which He loved us,
5 even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved),
6 and raised us up together, and made us sit together in the heavenly places in Christ Jesus,
7 that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus.
8 For by grace you have been saved through faith, and that
not of yourselves; it is the gift of God,
9 not of works, lest anyone should boast.
Romans4:14 Seeing then that
we have a great High Priest who has passed through the heavens, Jesus the Son of God, let us hold fast our confession.
15 For we do not have a High Priest who cannot sympathize with our weaknesses,
but was in all points tempted as we are, yet without sin.
16 Let us therefore come boldly to the throne of grace, that we may obtain mercy and find grace to help in time of need.
How can a saved person come boldly to the throne of grace and ask for mercy and find grace if his sin is unpardonable? By this scripture and a million others he cannot, because there is no unpardonable sin for those saved by grace through faith. See Below. You didnt save yourself to start with so how can you lose what you didnt earn, you were given!
Romans 6:23 For the
wages of sin is death, but the
gift of God is eternal life in Christ Jesus our Lord.
Hebrews 6:1-8 1 Therefore, leaving the discussion of the elementary principles of Christ, let us go on to perfection, not laying again the foundation of repentance from dead works and of faith toward God,
2 of the doctrine of baptisms, of laying on of hands, of resurrection of the dead, and of eternal judgment.
3 And this we will do if God permits.
4 For it is impossible for those who were once enlightened, and have tasted the heavenly gift, and have become partakers of the Holy Spirit,
5 and have tasted the good word of God and the powers of the age to come,
6 if they fall away, F26 to renew them again to repentance, since they crucify again for themselves the Son of God, and put Him to an open shame.
Verses 4-6 are saying 1 of 2 things.
1. You cannot fall away.
2. If you do fall away you cannot be renewed to repentance lest you put Christ to open shame.
However thats not to say works are not integral to salvation because the bible tell us that our faith must bear fruit. If you are truly saved you will bear fruit.
John 15:5 I am the vine, you are the branches. He who abides in Me, and I in him, bears much fruit; for without Me you can do nothing.
This clearly says if you are saved you WILL BEAR fruit. Its not an IF statement Christs says you will bear fruit. If you never bear fruit, you were never saved in the 1st place.
James 2:14 What does it profit, my brethren, if someone says he has faith but does not have works? Can faith save him?
15 If a brother or sister is naked and destitute of daily food,
16 and one of you says to them, "Depart in peace, be warmed and filled," but you do not give them the things which are needed for the body, what does it profit?
17 Thus also faith by itself, if it does not have works, is dead.
18 But someone will say, "You have faith, and I have works." Show me your faith without your works, and
I will show you my faith by my F7 works. 19 You believe that there is one God. You do well. Even the demons believe--and tremble!
20 But do you want to know, O foolish man, that faith without works is dead?
21 Was not Abraham our father justified by works when he offered Isaac his son on the altar?
22 Do you see that faith was working together with his works, and by works faith was made perfect?
23 And the Scripture was fulfilled which says, "Abraham believed God, and it was accounted to him for righteousness." And he was called the friend of God.
24 You see then that a man is justified by works, and not by faith only.
25 Likewise, was not Rahab the harlot also justified by works when she received the messengers and sent them out another way?
26 For as the body without the spirit is dead, so faith without works is dead also.
This is all straight out of the king james and taken in context.