Let's start with agreeing to approach the context in humility. Using the science of interpretation, how are you concluding that there's a sin that is unforgivable since that concept is competently false in the rest of the bible. So how do you handle this one passage and it's the only passage, the only context in which it is found?
From the first century Jewish perspective a completely sufficient explanation is given.
Not really my brother.
#1.
Matthew 12:32
"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".
#2.
Mark 3:28-29
" Verily I say unto you, All sins shall be forgiven unto the sons of men, and blasphemies wherewith soever they shall blaspheme: But he that shall blaspheme against the Holy Ghost hath never forgiveness, but is in danger of eternal damnation."
So we do in fact have the witness of two.
Then let us examine Matthew 12:32 carfully. The word "UNPARDONABLE" is not in the Scripture at all.
The literal words are...."It shall not be forgiven" . Therefore, if there is a sin that shall not be forgiven in this life or the next, then that sin is unpardonable. That means "CAN NOT BE PARDONED". The penalty must be paid!!!
If God should forgive one who had committed this sin, then He would cease to be God. God can not and will not forgive one who has committed the unpardonable sin.
So, what is sin????
The Bible gives us the answer in John 3:4.....
"For sin is the transgression of the Law".
So then, what is the Law?
The Law is the revealed will of God in regard to human conduct, including all the Divine commands and precepts proclaimed through Moses.
We are not under Law, but God's Law has not been destroyed or altered. Jesus came into this world in a body of humiliation and in that body He fulfilled every jot and tittle of the Law of God. (Matt. 5:17)
What is "Blasphemy"????
It is irreverence toward anything regarded as sacred. It is indignity offered to God, either in words, or writing or signs with those things claiming the attributes of God. That is from the Webster's dictionary describing what blasphemy was in Jewish customs.
So, what did these men do to whom Jesus spoke these words?
Jesus healed a boy that was possessed with a demon and they said that He did it by the power of Beelzebub, the prince of all demons. Thay gave credit to Satan for the miracle Jesus had done through the Spirit of God. Therefore they spoke IRREVENTLY against the Holy Spirit.
To speak against the Holy Spirit is to speak against God.
John 6:44.......
" No man can come to me except the Father which hath sent Me draw him, and I will raise him up at the last day".
And how does God draw a sinner to Christ?????
Through the power of the Holy Spirit.
John 16:7-8
"Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you. And when he is come, he will reprove the world of sin, and of righteousness, and of judgment".
The Spirit of God draws men to Christ. The Spirit uses the Word which is the light, the sword, the hammer, the fire, the incorruptible seed, the bread and the water. The Spirit uses the Word to convict men of their sin and point them to Christ.
Luke 13:3 says.........
"Except ye repent, ye sall all likewise perish".
The Spirit of God not only draws us, He borns us and then indwells us and seals us. So then, what is it that can never be forgiven???????
To refuse, to reject to come to Christ WHO the Holy Spirit has drawn the sinner to is the sin which can not be forgiven, IF...IF that sinner dies in his sin..........He has rejected the salvation offered by the Lord Jesus Christ. One who has "blasphemed" the Holy Spirit has no desire to be saved and when death comes for them.......they will ne lost sinners and the wages for sin is death.