There are 3 passages that we have to consider. We will briefly look at the first two and then concentrate on the passage in Mark.
Reference to the strong man’s house (Isaiah 49). The issue is about authority. Jesus comes with a sign that can only be interpreted as God acting among the people. Acknowledging this sign is a clear separation between those who understand who Jesus is and who He represents. To reject the implied authority is to reject the One who sent Him. As Jesus says, “If you are not with me, you are against me.”
The expression in Luke reminds us of many OT passages. Leviticus 24:11-23, Numbers 11:17 and 27:18, Numbers 15:30-31, Deuteronomy 34:9, Psalm 106:32-33.
The first thing we need to understand is what is blaspheme.
The Hebrew word that parallels the Greek for blasphemy is ne’asa. It signifies the action or attitude where the former recipient of favorable disposition and/or service is consciously viewed and/or treated with disdain. Consider the following synonymous parallels: mārâ “to rebel against authority” (Ps 107:11); ˒ābâ “to be unwilling and disinclined toward obedience” (Prov 1:30); śānē˒ “to hate” (Prov 5:12), not believing in the Lord (Num 14:1), to forsake God (˓āzab, Isa 1:4), mā˒as “to reject,” Isa 5:24, ḥārap “to say sharp things, reproach, scorn” (Ps 74:10).
Notice that it is not about swearing. It is actions, attitudes and words.
But God does forgive our disobedient actions, our sinful attitudes and our vile speech. So, what’s different about this particular sin?
Now we can look at the passage in Mark.
First notice the formula expression of this verse (Truly, truly – amen lego humin). What does that tell us? This is the first time that this formula is used in Mark.
This expression establishes authority. That is the real issue at stake in this passage. The authority of God manifest in His saving grace
We must understand the issue of authority before we can answer the next critical question: Who is the one who blasphemes in this verse?
We must look at the context
The passage begins in verse 20
What is the story? The scribes contend that Jesus casts out demons through the power of Satan. Why do they say this?
Jesus replies that if this were the case, Satan would already be defeated.
Then Jesus alludes to the lesson of the strong man and the strong man’s house.
Where does this metaphor come from?
Consider Isaiah 63:10: This is the only passage in all the OT that speaks of grieving God’s Holy Spirit. Here the Hebrew word is atsav, usually translated as sorrow and emotional agony. The same word is used in Genesis 3 to describe the results of the Fall. Here it is a Hebrew verb tense that indicates an active cause. In other words, what these people did had a direct effect on the Spirit of God. Their actions caused something to happen.
What is happening in this passage in Isaiah?
First, it’s a passage about the messianic Servant. Consider the context:
The One who comes to save, garments of red, alone, life blood sprinkled on His clothing, producing salvation by His own arm.
He is filled with lovingkindness and mercy. He appeals to His own people. He heals their affliction and redeems them.
But they rebel against Him. They grieve His Holy Spirit. As a result, He becomes their enemy rather than their savior.
Notice that the description of the messianic savior here echoes the character of God in Exodus 34:6. The character of God is merciful, except note the consequences of rejection of that mercy in Exodus 23:21. Notice that here God says He is sending a representative who carries the authority of His name. Rebellion against God’s representative leads to the impossibility of forgiveness. Why? Because this rebellion denies the authority of God by insulting His name. To deny the authority of the messenger is to deny the authority of the One who sent him.
When Jesus alludes to these OT passages, he shifts the question to one of authority. Just as there were rebellious members of Israel in the first exodus, now there are rebellious members of Israel in the second exodus. Jesus is the second Moses. He is sent in the name of the Father to bring rescue and redemption. But there are those among His own people who deny His authority by suggesting that His power is demonic. In the first exodus, God did not forgive the rebellion of the Israelites. The entire generation died in the wilderness.
Isaiah 63:17 fills in the picture. God hardened their hearts (note the Hebrew verb here)
There are three possibilities for understanding the Greek verb poroo as a Hebrew translation. We can see all three in the description of Pharaoh’s response to God. They are all translated “hardened” in English, but that only means that we don’t understand the nuances – and the nuances make a big difference. The first possible word is hazak. Although it is translated “hardened” in verses like Exodus 4:21, that translation doesn’t really communicate what is happening because hazak normally means “to strengthen” and is most often applied to the idea of “power” (as in “a mighty hand”). When this word is applied to Pharaoh, it means that Pharaoh is unyielding. God simply allows Pharaoh’s natural resistance to be strengthened so that Pharaoh does not relent. The second word is kaved. It means “to make weighty or heavy,” implying either honor or dullness (Exodus 9:7). God allowed Pharaoh’s heart to become dull, that is, to move in the direction of the natural man who does not discern the things of the Spirit, simply by withdrawing common grace. We can see the connection between hazak and kaved. Both involve God allowing the rebellious soul to act without spiritual intervention.
Then there is the third Hebrew word, the one that Jesus probably used. It is qashah. You will find it in Exodus 7:3. It means to become obstinate, resistant or stubborn. You’ll find it in Jeremiah 7:26. Why is it likely that Jesus used this word instead of the others? Because this is the word the prophet uses to describe the condition of disobedient Israel. It is the word for not paying attention to the power and majesty of God. It is applied to the children of Israel in the wilderness and prior to the Captivity. It is about a nation that didn’t listen to those who were sent to from God (see Jeremiah 7:23). When Jesus uses this word, the culpability falls directly on His audience. They resist what God displays.
As a result of this rebellion, they are put to death.
It is possible to reject Jesus as the Messiah during His earthly ministry. Jesus comments on this possibility in the Luke passage. But grieving the Spirit is more than rejecting the demonstration of Jesus as the Messiah while He is on the earth. Grieving the Spirit is the consistent and deliberate resistance to the power of God to save through His anointed One. In other words, while men may reject the Messiah during the time that Jesus brings the message of God’s grace and still be forgiven for that sin, anyone who continues to resist the Spirit excludes himself from the grace of God, with the result that he cannot be forgiven and becomes God’s enemy. To ultimately reject the Messiah by refusing repentance means that forgiveness is not available and can never be available. There is no other means by which we must be saved.
There is a parallel in Jeremiah 5:12 – a denial of the fact that God is the God of authority. The result is utter destruction. To suggest that Jesus’ authority is from Satan is to lie against God. The result will be destruction, just as the prophet said.
Furthermore, Jesus as the messiah is the final revelation of God’s mercy. To insult His authority is to reject the last hope of redemption. There is no other coming rescue, and therefore, no other possibility of forgiveness.
So, there is more here than simply to cut oneself off from future forgiveness by rejecting God chosen One. As Isaiah shows, this rejection turns God from one who provides redemption to one who brings vengeance. This makes God my enemy.
So, who is the one who blasphemes? Jesus points to the religious leaders (the scribes) who should have known the authority of God in the messenger but who denied that authority. For them, there is no forgiveness. God becomes their enemy.