Mark 7:28 “Assuredly, I say to you, all sins will be forgiven the sons of men, and whatever blasphemies they may utter; 29 but he who blasphemes against the Holy Spirit never has forgiveness, but is subject to eternal condemnation”— 30 because they said, “He has an unclean spirit.”
I find that many Christians are confused on this sin which Jesus said is unforgivable. As word in the Bible we must carefully study this, and try not to guess by presuppositions so that we do not naively err.
So let’s examine this unforgivable sin
Blasphemy is defined as “a spoken word against”. You must verbally say something in order to blaspheme. In this case it is a spoken word specifically against the Holy Spirit.
In this case, the Pharisees claimed Jesus was doing His miracles and works by the power of Satan not by the Holy Spirit. They specifically attributed the work of the Holy Spirit to Satan, a spoken word against the Holy Spirit. This is the unforgivable sin. Mocking the Holy Spirit, saying He did something evil, saying that He is not God, ridiculing His regeneration, attributing His works to someone else like Satan, this is the specific sin Jesus was speaking about.
The common mistake is to presume unbelief in Jesus is unforgivable. If this were the case, no one could be saved. There is no forgiveness after death, but this singular specific sin Jesus was speaking about will have had to be committed in this lifetime. In both cases, the result is eternal hell, however one dying in unbelief may never have committed the unforgivable sin. Their sins which have not been forgiven was their ticket to eternal hell. Can an unbeliever also blaspheme the Holy Spirit, the answer is yes. But these are two separated premises, their unbelief and the blasphemy they would have committed. Unbelief is a sin which would be forgivable in the life of a sinner whereas blasphemy, the spoken word against the Holy Spirit, in the life of the sinner is unpardonable, it will never be forgiven.
For example we see this reference Mark 9:24, “Immediately the father of the child cried out and said with tears, “Lord, I believe; help my unbelief!” For those who falsely claim blasphemy of the Holy Spirit is unbelief, this father could not be forgiven nor would Jesus pay him no mind. In order for it to be unpardonable, the father would have had to say “I will only believe in God by the power of Satan, never by the Holy Spirit”.
The unforgivable sin will usually be committed by someone of a world religion, someone who knows and believes the Holy Spirit exists and that evil exists. Their hearts being so darkened will blaspheme Him. The true atheist will not commit this sin, because they don’t believe either the Holy Spirit or evil exists, thus they will not speak a word against Him or they would contradict themselves. Now the atheist who dies in unbelief will die without their sins being forgiven, so they will go to hell for this reason, not because of blasphemy of the Holy Spirit.
The unpardonable sin is a specific singular sin and it is clear what Jesus explained. It is a spoken word against the Holy Spirit. The person committing this sin KNOWS what they are doing. This sin will be committed in this lifetime, so the verdict on someone who committed this sin is already in.
Having witnessed to atheists, I for one have never heard blasphemy against the Holy Spirit from them. But witnessing to Roman Catholics and other world religions, I have witnessed SEVERAL times some coming dangerously close to committing that sin. An example would be if they were to say Satan regenerated the heart of a Christian, or the Gospel being shared by that Christian is of Satan. My personal experience is to provide a warning on this blasphemy, and if they continue on, generally I can discern the person as so dark hearted they really do not care if they blasphemed the Holy Spirit or not. The fear of God is non-existent in such a person.
A new creation should never be able to commit this sin, as the Holy Spirit is indwelling them, nor would they flirt with committing it either. The sin is almost always committed by a worldly religious zealot who has set their terms for God on what He can do or He cannot do, and will willfully commit this sin.