License to Exhort
License to Exhort
OT Scripture: Psalm 119:129-136
NT and Sermon Scripture: Hebrews 3:12-19
Introduction
What makes a heart harden?
Physically speaking, it happens when blood vessels lose their flexibility. Over time, plaque builds up. Blockages form. The flow of life is slowly choked off.
This past week, a pastor who deeply influenced me, Voddie Baucham, passed away. Pastor Voddie had long battled heart disease. In 2021, he underwent a quadruple bypass surgery. So when the news came that he had suffered a medical emergency, many assumed it was heart-related.
Now perhaps you don’t have heart disease this morning—or at least you don’t know of it. And you are not concerned at all about having a cardiovascular medical emergency. But doctors often call heart disease a silent killer. Why? Because it creeps up slowly. The vessels harden little by little. The arteries narrow. The flexibility is lost. And one day, the damage becomes fatal. Not all at once, but gradually—through poor diet, lack of exercise, or simply through the frailty of our human condition.
And just as there is danger to our physical hearts, there is danger to our spiritual hearts. That is what the writer of Hebrews warns us about in this passage. A spiritual heart does not turn hard overnight. It happens little by little—through small compromises, neglected habits of faith, the deceitfulness of sin—until the flow of spiritual life is cut off.
That’s why, as we prepare to launch the rest of our Bible classes in the coming weeks, I want to stress their importance for us as a church. These gatherings are not just programs or add-ons—they are one of the means God uses to guard us from spiritual heart disease, to keep our faith alive, soft, and responsive to His Word.
To do this, I want to make three movements this morning:
- First, we’ll look at the temptation the recipients of this letter were facing.
- Second, we’ll look at the warning they received.
- Finally, we’ll consider the message God has for us today.
The Temptation: Returning Back to Judaism to Relieve Persecution
The Recipients
The recipients of the letter to the Hebrews were deeply familiar with the Jewish system of rituals and sacrifices. They had been raised and catechized in the law of Moses, and their entire approach to God had been shaped by those laws. But in the midst of that system, they were introduced to Jesus—the One who fulfills all Old Testament promises.
He is the One who offers true spiritual rest. He is the One who satisfies the deepest longings of our hearts. He is the One who calms overwhelming circumstances—not by removing us from them, but by giving us peace in the midst of them, a peace that surpasses all understanding. The recipients of this letter came to see that Jesus was better. He was more glorious, more powerful, more mighty than anything they had encountered before. In him, the thirst of their yearning hearts was quenched. In him, the desires of their souls were met. That is the Jesus who had impressed them.
And why were they so impressed with him? Because they were steeped in the Old Testament.
Jesus is the fulfilment of all OT promises, and because of this, the author of Hebrews is beginning to unpack how Jesus is better than the shadows of the OT.
The whole Bible is about Jesus. He is the way back to the Father, and there is no salvation apart from him. He forgives the wickedness of our sins, and reconciles us to God. If want to learn more about that, ask me after the service.
But here lies the writer’s concern: these Jewish believers had found the fulfillment of the Mosaic covenant in Christ, but now they were facing persecution for their newfound faith in the promised Messiah.
The Problem – Easy Faith
Here’s why this became such a problem. Judaism was already recognized by Rome. Judea was a Roman province, and the Mosaic rituals and ceremonies were tolerated as part of an established religion. But Jesus entered the scene declaring himself Lord—claiming first place, claiming to be the true Sovereign, the true Emperor of the world.
That allegiance to Christ put believers in direct conflict with Rome. To confess “Jesus is Lord” meant “Caesar is not.” Rome wasn’t overly threatened by Mosaic Judaism—it lacked a king, and its practices were manageable. But a new movement rising up, declaring a higher King, a new Lord—that Rome could not tolerate. And so persecution followed.
This is the dilemma the writer of Hebrews is addressing. Some believers were tempted to say, “If God accepted us under the Mosaic covenant, can we not just return to the old ways? Can we still be devoted to God but avoid this hostility, this persecution, this danger that comes from proclaiming Christ as Lord?” The temptation was clear: return to Judaism to relieve persecution.
Now, from our vantage point two thousand years later, it may seem obvious: of course Jesus is better. But remember—these believers were as human as we are. And just like them, we are tempted to minimize hardship. We prefer the easy road over the road of suffering. If given the choice, we would choose the wide road every time. Yet following Jesus is always a call to deny ourselves.
Our Problem – Easy Faith
Maybe your temptation isn’t to return to Judaism. But you and I are constantly tempted to water down the commitment God requires of us. And notice—these early Christians weren’t saying, “We don’t want to be devoted to God anymore.” What they were really asking was, “Can we be devoted to God in a way that isn’t so countercultural? Can we find a middle ground? Can we have the best of both worlds?”
But it seems that the recipients of this letter had not fully thought through what it would mean to approach God again through the Mosaic covenant. They had not carefully considered all the implications of trying to come to God through a system that had already been fulfilled in Jesus Christ. As one commentator puts it, returning to the Mosaic covenant would be like trying to go back to the jet bridge once the plane has already taken off. If you turn back after the plane has departed, the consequences are deadly. The writer of Hebrews makes the same point: if you try to access God through the old system after boarding the new covenant in Christ, you will not reach your destination—eternal life.
So, what would happen if they try to access God through the mosaic covenant having experienced the new? Could they return back to Judaism without any negative repercussions?
The answer from Hebrews is a sobering no. To turn back is to forfeit God’s rest. That is why the writer gives us such a serious warning. And that’s why I want to draw your attention to verse 12…
The Warning: The Dangers of an Unbelieving Heart
In verse 12, the writer of Hebrews gives a sobering charge. He takes words first spoken to the wilderness generation—and later applied to David’s generation—and now applies them to the readers of his letter:
“Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.”
The warning is clear. If these believers abandoned Jesus—the One who is better—in order to return to the old covenant system, they would be in danger of falling away, showing that they had never truly believed. To turn away from Christ is to turn away from the living God—the God who gives life, the Father of mercies.
Notice the urgency. The author says, be careful, watch out! He wants his readers on guard, because an unbelieving heart will cause them to fall away. But beneath this warning lies a deeper reality: unbelief is how sin manifests itself. The very nature of sin is doubting God and his promises. That’s why the author pleads, “Be careful, lest any one of you…”—from the smallest to the greatest, from rich to poor, the whole congregation. Because unbelief is the telltale sign of sin. A hardened heart is what Scripture calls apostasy—denouncing God’s promises and forsaking the living God.
The author grounds this in a conditional statement. In verse 14 he writes:
“For we have come to share in Christ, if indeed we hold our original confidence firm to the end.”
In other words, you have already tasted the blessings of Christ. You have shared in the fellowship of the Spirit. You have experienced the goodness of God’s Word. You have glimpsed the powers of the age to come. But all of this is true only if you continue to abide in Christ until the end.
If you turn back—if you try to make following God more socially acceptable, less costly, less confrontational—you are no longer approaching God through the way he has appointed in Christ. You are trying to approach him on your own terms, in your own wisdom, by your own way. If you persevere, you share in Christ. If you do not persevere, you never truly shared in Christ. You would be like a branch connected to the vine but bearing no fruit. Like a cloud with no water. An external Christian, but not an internal one.
That is why verse 15 presses the urgency again:
“Today, if you hear his voice, do not harden your hearts.”
The writer is echoing Psalm 95, which he already quoted earlier. In that psalm, the Holy Spirit recalls Israel’s rebellion in the wilderness. Though they had seen God’s mighty acts in Egypt and his mercies in the desert, they hardened their hearts. They refused to believe and obey. And so they were barred from entering the promised land. The psalmist then applies that lesson to his own generation: Today, if you hear his voice, do not harden your hearts. But tragically, Israel did not listen—and exile followed.
Now the writer of Hebrews takes up that same word “Today” and applies it to us. Christ has come. We have tasted the heavenly gift in him. But if we refuse to obey—if we harden our hearts and reject the better way of Christ—we too will not enter God’s eternal rest.
To drive this point home, the author begins to quote psalm 95 and ask some questions. He asks in verse 16: “Who were those who heard and yet rebelled?” The answer: all those who came out of Egypt under Moses. His focus is on the quality of people. In other words, those who saw all the signs and wonders and heard God’s voice, and yet disbelieved. And if disbelieving Moses—the faithful servant in God’s house—brought such severe consequences, how much more serious is it to disbelieve Jesus, the Son, the One who rules faithfully over God’s house?
In v. 17, the author moves from the quality of people to the duration of time that God was calling his people toward obedience. They died because of unbelief, when they could have lived through faith.
In v. 18, the author brings the warning to the climax: God swore that his people would not enter into rest. At that point, nothing else could be done. They were effectively barred from entering God’s rest. And the reason for all of this is, as stated in v. 19: unbelief! Because of their unbelief they tested God, went astray, rebelled, and had hardened hearts. The author returns back to the idea of v. 12, unbelieving hearts!
And so the question comes to us: why didn’t they believe? Why did their hearts harden? Verse 13 gives the answer: they were hardened by the deceitfulness of sin. Sin blinds. Sin deceives. Sin deadens the heart. Faith in God’s promises through Christ is the antidote, but sin is the poison that kills faith.
And so the writer urges us with holy urgency: Do not let your hearts grow hard. Believe God’s promises—today. Let your hearts be pliable attentive eager to do what the Lord is commanding and don’t resist his will.
The Message: Avoid A Hardened Heart!
What is the message that the writer of Hebrews wants to communicate to the recipients of his letter? What is the fundamental point?
The message is this: Avoid a hardened heart.
These believers were beginning to suffer. They were tempted to return to the Mosaic covenant. They wanted an easier path to heaven. They longed for the reward of eternal rest without having to endure the loss that comes in this life. They were being persuaded—pressured by their society—to abandon Jesus.
And the author is saying to them: Avoid a hardened heart.
In other words: Be on guard against the deceitfulness of sin by exhorting one another to hold fast to God’s promises in Christ.
How Do We Avoid a Hardened Heart?
That’s the question. How do you keep your heart from becoming calloused and resistant to God’s Word? How do you stop your heart from being catechized—discipled—by your own desires, by culture, or even by Frank Sinatra’s “My Way”?
Hebrews 3:13 gives us three ways:
- Recognize That Your Heart Is Easily Deceived
You and I are far more susceptible to deception than we want to admit. And the enemy we face is not just outside of us. It’s inside of us.
Our hearts have a natural disposition to trust our own thoughts more than God’s thoughts. If we fail to recognize that reality, then we won’t see that there’s a silent killer within us—an enemy slowly chipping away at our confidence in God.
You might say, “I will never leave Jesus!” Peter said the same. Our hearts are easily deceived!
Your heart is being trained daily. My heart is being trained daily. The question is: what is training it? Is it being instructed toward godliness—or toward ungodliness?
Your heart is not neutral. My heart is not neutral. That’s the first step: recognize your heart is vulnerable and easily deceived.
- Understand the Deceitfulness of Sin
The writer doesn’t just say, “Be careful lest you be hardened by sin.” He says:
“Be careful that none of you may be hardened by the deceitfulness of sin” (v. 13).
Why? Because sin always promises what it cannot deliver.
Think of Eve in the garden. The fruit promised wisdom and pleasure. But the joy lasted only a moment before it turned into shame and fear. Sin always masks its true intentions. It offers something you genuinely want—sometimes even something good—but it hides the destruction behind it.
That’s how sin works in us. It tricks, it masquerades, it convinces. It whispers: “This will make you happy.” But it cannot deliver what it promises.
That’s why the author warns us: beware of the deceitfulness of sin.
- Exhort One Another Daily
Finally, how do we avoid a hardened heart? By exhorting one another.
Look at verse 13:
“But exhort one another every day, as long as it is called ‘today.’”
As long as we are on this side of eternity, the command is clear: exhort one another. Not sometimes. Not occasionally. Every day.
That’s why I titled this sermon “License to Exhort.” In our denomination, a license to exhort is given by classis after an examination, certifying that someone is permitted to bring God’s Word to the churches.
But here’s the point: every Christian has been given a license to exhort. Not necessarily in the pulpit, not necessarily leading a congregation—but in daily, interpersonal ways. Parents exhort children. Husbands and wives exhort one another. Friends exhort friends. Brothers and sisters exhort brothers and sisters.
Look at QA 32 of our Catechism:
Q & A 32
- But why are you called a Christian?
- Because by faith I am a member of Christ1
and so I share in his anointing.
I am anointed
to confess his name,
to present myself to him as a living sacrifice of thanks,
to strive with a free conscience against sin and the devil in this life,
And one of the main ways we do this is through Bible studies. Notice this is not optional. The writer of Hebrews says: “as long as it is called today.” That means as long as we’re on this side of heaven, as long as the fight of faith continues, exhortation is necessary.
Next week, our various Bible studies will begin again—women’s, men’s, youth, and children. These are not just programs. They are God’s way of protecting us from hardened hearts.
Did you hear that? God is protecting us from hardened hearts when we engage in Bible studies. παρακαλέω – to summon, exhort, encourage, comfort, implore
παράκλητος – helper, (legal) assistant, advocate
What is one of the ways that the Spirit of God helps us, assist us? Through our Bible studies!
Now, if we don’t believe that we are in danger of being deceived, then we can go on our marry way, but the threat of deception is continual, and any conclusion beyond that would be to miss the instruction of this text. Look at vv. 16-19 again. The writer of Hebrews tells us that the people who didn’t make it to the promise land were people who saw with their own eyes all of God’s miracles in the wilderness. These weren’t newbies, or who joined the party late. They were participants from the very beginning and yet their hearts were hardened. Our hearts are capable of being hardened!
But the way God causes us to persevere until the end is by helping us exhort one another as long as it is “today,” that we would not be hardened by the deceitfulness of sin.
Let me put it provocatively: Bible studies are one the statin for your heart health. If you want to avoid spiritual heart disease, you must engage in God’s Word with God’s people. There is no spiritual growth apart from it.
Think about your relationships. How often do you talk about the same topics with those you love? Husbands and wives circle back to the same conversations. Parents repeat the same lessons to their children. Friends retell the same stories. That’s how relationships grow—by revisiting and rehearsing what matters most.
The same is true with God’s Word. We don’t move past it. We return to it again and again because this is how God communes with us. He reminds us of His love in Christ. He reassures us that nothing can separate us from Him. He calls us to holiness, but also comforts us with His mercy.
That is why when Paul was describing the new covenant community in Colossians 3, he says, “let, allow, make in effort for the word of God to dwell in you all richly.” He didn’t say barely let it dwell in you, or a lot, he said richly, overabundantly, overflowingly.
So don’t dismiss Bible study as something you already know. Engage in it. Because it is life for you. It is God’s voice speaking to you. It is the very means God uses to keep your heart soft and alive.
Avoid a hardened heart by recognizing your vulnerability. Avoid a hardened heart by resisting sin’s lies. Avoid a hardened heart by exhorting one another daily.
Avoid a hardened heart. Exhort one another. And keep believing the promises of God in Christ.
Conclusion
This morning, the warning is clear: beware of a hardened heart. Beware of a deceived heart. Beware of an indifferent heart.
And how do we avoid such a heart? By engaging the Spirit’s work among us—by exhorting, encouraging, and comforting one another with the sweet truths of the gospel.
So as you look ahead, make it your ambition—if you haven’t already—to join a study group. These are not optional add-ons; they are God’s provision to keep your heart soft. And once you join, make it your ambition to be faithful—to show up every time—because sin is tricky, and our hearts are easily deceived.
Let us not drift into hardness. Let us actively exhort one another. For by God’s Spirit, each of us has been given a license to exhort!