What is the Unforgivable Sin? This issue is raised in Matthew 12:31-32:

Therefore I tell you, every sin and blasphemy will be forgiven people, but the blasphemy against the Spirit will not be forgiven. And whoever speaks a word against the Son of Man will be forgiven, but whoever speaks against the Holy Spirit will not be forgiven, either in this age or in the age to come.

First, every other sin and blasphemy will be forgiven. Did you see that? Every other sin. No matter what you’ve done to others, or yourself, you can receive forgiveness on one condition: if you confess and turn from your sin and surrender to Christ and Christ alone, you can receive forgiveness. First John 1:9 says, “If you confess you sins, he is faithful and just to forgive us our sins and cleanse us from all unrighteousness.”

Let’s address the first one: what is sin? Sin is any violation or transgression of the law of God. Romans 3:23 sums it up nicely: “All have sinned and fallen short of the glory of God.” So, any shortcoming of God’s glory is sin. When R.C. Sproul attended school in the Netherlands, he noted that Dutch society “was governed by a vast number of laws that defined every aspect of life.” He recalled a frequent expression: “You have overstepped the law.” It’s a sin of commission: doing something you’re not supposed to do; and omission: not doing something you’re supposed to do.

What about blasphemy? Blasphemy comes from Gk. Blasphemia. Blas means sluggish/slow, while pheme means reputation/fame. It’s a slowness to call something good or to identify what is truly bad. This perfectly describes what the Pharisees were doing—being slow to call something good. If you read the context, a man was freed from demon possession by Jesus, but the Pharisees were sluggish to attribute the power to God (why?) because then they would have to admit that Jesus came from the Father. And they weren’t about to do that in a million years.

Forgiveness is not the same as, “Ah, don’t worry about it!” Forgiveness means that that sin was paid for through a death—and the subsequent shedding of blood, without which there is no forgiveness of sin. The Pharisees oversaw sacrifices of lambs and bulls and goats for the forgiveness and atonement of sins. They knew that a death needed to happen to those animals for life to be possible for God’s imagebearers. A high, high price was paid for our forgiveness. In fact, soon after this encounter, the Lamb of God, Jesus Christ, would go to the cross and shed his blood for the forgiveness of our sins.

So why this sin? Does not the blood of the Lamb and Christ’s forgiveness cover all sin? Why does it not cover this sin? Why is this particular sin of blasphemy of the Holy Spirit not covered? Let’s take a look.

At first glance, it seems that the Holy Spirit is, yes, equal amongst the members of the Trinity, but he’s more equal than Jesus. But first glances aren’t the best way to approach anything. Deep study is what’s needed here.

First, in this instance, this is referring to Jesus while he’s here on earth, for while on earth, Jesus looked like an ordinary Jewish man who worked in a carpenter shop with his adopted dad for most of his life. Isaiah 53:2-3 gives an idea:

For he grew up before him like a young plant,
and like a root out of dry ground;
he had no form or majesty that we should look at him,
and no beauty that we should desire him.
3 He was despised and rejected by men;
a man of sorrows, and acquainted with grief;
and as one from whom men hide their faces
he was despised, and we esteemed him not.

Philippians 2:7 said that, though he was holy God, came in the form of a servant and became obedient unto death, even death on a cross. He was considered not just an ordinary human, but was treated like a common criminal.

So, it would be forgiven them should they simply see Jesus as a common, ordinary man.

Secondly, it’s about the Holy Spirit’s revelation of God’s power, most represented in Christ (John 16:12-15). This is where it’s important to understand the Holy Spirit’s role more than we do.

12 “I still have many things to say to you, but you cannot bear them now.13 When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. 14 He will glorify me, for he will take what is mine and declare it to you. 15 All that the Father has is mine; therefore I said that he will take what is mine and declare it to you.

There will come a time when the Spirit of truth will come to (1) guide you into all truth, (2) speaking on the authority of the Father, (3) he will let you know what’s to come, (4) will glorify Christ and declare all that He is to you.

Let’s go back to the beginning: the Pharisees attributed Jesus’ miracle of freeing a demon-possessed man to the fact that empowering Jesus to free him was the power of Satan, not God—so they rejected and blasphemed the Spirit that brought the power of God.

So Jesus tells his disciples that one day, he would leave them, but the Spirit would come. But if you reject the Spirit, slander the Spirit, it’s unforgivable because you are slandering and denying the one that guides you into all truth, speaks on the Father’s authority, and most importantly reveals and glorifies Christ as the way, the truth and the life and brings our awareness of our sin and an applying of our salvation that Jesus accomplished. In other words, if you deny the Spirit’s word about Christ’s saving work for you, that is unforgivable. You are denying and rejecting the very Person who accomplished the very act that can forgive you and redeem you and atone for your sins in the first place.