Hebrews 3:7-19

Most things do not become hard all at once.

Think about concrete. When it is first poured, it is soft. You can move it, shape it, smooth it out. But once it sits there long enough, it begins to set. And eventually, what was once soft becomes hard.

Our hearts can work the same way.

Very few people wake up one morning and decide, “Today, I am going to walk away from God.”

It normally happens little by little.

We hear God’s Word, but we ignore it.

We know what God has commanded, but we put off obeying it.

We know what God has promised, but we allow our circumstances to speak louder than His Word.

And every time we resist the voice of God, there is a danger that our hearts become just a little harder.

That is the warning before us this morning.

The author of Hebrews is going to take us back to a generation of people who saw the mighty works of God with their own eyes, yet still hardened their hearts against Him.

And through their story, the Holy Spirit gives us this warning:

“Today, if you hear his voice, do not harden your hearts.”

And that brings us to our main point this morning:

Because Jesus is better, we must hear His voice, guard our hearts from unbelief, and hold fast to Him to the end.

So as we walk through this text, I want us to hear this warning not merely as something that happened to Israel thousands of years ago, but as the Word of God speaking to us today.

Do Not Harden Your Heart (7-11)

Even though we have been deep in the realms of Christology, we are now about to consider something that is especially easy to comprehend.

I am sure that as we just read these twelve verses, you understand the argument the author is bringing us to. However, it would be wrong for us to understand this section, as convicting as it is, without understanding the previous verses we have already considered.

We have been shown that Jesus is better than the prophets who came before Him, the angels who serve under Him, and even Moses. We have been exhorted not to drift away from what we have heard. We have been told to consider Jesus and to hold fast to our confidence and our boasting in our hope.

These Jewish Christians understood their Old Testament. They knew of the flight of Moses and the Israelites that we studied throughout our series in Exodus. They knew the narrative of Numbers, the promises and laws of Leviticus, and the book of Deuteronomy. Furthermore, they knew of Moses’s faithfulness and the foolishness and faithlessness of the Israelites who traveled throughout the wilderness.

They understood the pain of the exile and the rebuilding of the temple. They sang the Psalms, including Psalm 95, which is going to be quoted here several times.

The author of Hebrews is doing something very similar to what Paul does in 1 Corinthians 10:1–13. He points the hearer back into the lives of the Israelites and uses them as a warning for the Christians who are hearing today. Paul even says in 1 Corinthians 10:6, “Now these things took place as examples for us.”

In other words, we are not supposed to read about the wilderness generation and simply shake our heads at their foolishness. We are supposed to see a warning for ourselves.

The Word given through the Holy Spirit in Psalm 95 gives an exhortation to the hearers not to harden their hearts:

“Today, if you hear his voice, do not harden your hearts.”

For these Christians, they are being called to hold fast to their confidence and boasting in their hope in Christ Jesus as Lord. Yet there were some there, and there are some here today, who will hear the Word of the Lord and still harden their hearts.

This is something that has plagued humanity from the beginning. Men and women hear the Word of God spoken to them, yet because of their disobedience and unbelief, their hearts become hardened against that Word.

We have to understand that a hardened heart does not always begin with someone standing up and saying, “I reject God.” Sometimes it begins much more quietly. God speaks, and we refuse to listen. God commands, and we make excuses. God promises, and we refuse to trust Him. God warns, and we convince ourselves that the warning really does not apply to us.

And little by little, the heart becomes hardened.

So let’s think this through as the author of Hebrews walks us back through the wilderness generation.

He brings up “the rebellion, on the day of testing in the wilderness, where your fathers put me to the test and saw my works for forty years.”

Remember the works that God had already done throughout Exodus.

God brought plagues upon the Egyptians. He delivered His people from slavery. He brought them safely through the Red Sea on dry land. He appeared to them in the pillar of cloud and fire. When they needed water, God gave them water. When they needed food, God provided manna from heaven.

Then He brought them to Mount Sinai, and there He showed them His glory in fire and smoke. They heard the thunder. They saw the mountain covered in smoke. They knew beyond any doubt that the God who had delivered them was with them.

We end Exodus with the construction of the tabernacle. And when the tabernacle is completed, the glory of the Lord fills it so greatly that even Moses cannot enter it (Exodus 40:34–35).

Think about that.

These people had seen the plagues. They had walked through the Red Sea. They had eaten the manna. They had drunk the water God provided. They had stood before Mount Sinai. They had seen the glory of God fill the tabernacle.

Their problem was never that God had failed to give them reasons to trust Him.

Their problem was that after everything they had seen, they still refused to trust Him.

God provides, and they complain.

God speaks, and they refuse to listen.

God promises, and they doubt Him.

God leads, and they want to go back.

Specifically, Psalm 95 points us toward two specific places: Meribah and Massah.

We remember the first incident from Exodus 17:1–7. The people of Israel found no water, and instead of trusting the God who had already delivered them, they quarreled with Moses. They demanded something to drink and even questioned whether God was truly with them.

Think about how foolish that question was.

“Is the LORD among us or not?”

God tells Moses to strike the rock, and water flows from it for the people to drink. Moses then names the place Massah and Meribah because the people quarreled and tested the Lord.

But then something very similar happens again in Numbers 20.

This time they are at Kadesh, near the end of Israel’s wilderness wandering. Once again, there is a shortage of water. And once again, the people begin complaining.

They even say, “Why have you brought the assembly of the LORD into this wilderness, that we should die here?”

Unbelief had become a pattern among the people.

Instead of looking at everything God had done and saying, “God has provided before, and God will provide again,” they responded to every new difficulty as though God had never been faithful to them.

God commands Moses to speak to the rock, and water would flow from it. But Moses, frustrated with the people, strikes the rock twice instead. Water still comes from the rock because God remains faithful to His people, but Moses himself is disciplined for failing to uphold God as holy before them.

And the issue running through both of these events, and really through the whole wilderness generation, is that they refused to trust God despite witnessing His works.

That is exactly what Hebrews 3:9 says:

“Where your fathers put me to the test and saw my works for forty years.”

They saw His works.

That is what makes their unbelief so serious.

They could not say, “We didn't know God would provide.”

They had seen Him provide.

They could not say, “We didn't know God could deliver us.”

They had seen Him deliver them.

They could not say, “We didn't know whether God was with us.”

His presence had been right there among them.

Their problem was not a lack of evidence. Their problem was an unbelieving heart.

And because of that unbelief, the wilderness generation would not enter the Promised Land. Their bodies would fall in the wilderness

They hardened their hearts when they complained instead of trusted, forgot instead of remembered, feared instead of believed, and rebelled instead of obeyed.

Hardness of heart doesn’t just start with, “I don’t believe in God anymore.”

God has provided, but I still don’t trust Him.

God has spoken, but I think I know better.

God has commanded, but I refuse to obey.

God has promised, but my circumstances seem more certain than His Word.

God has been faithful, but I keep acting as though He won’t be faithful this time.

This is why this exhortation is for today.

“Today, if you hear his voice, do not harden your hearts.”

Not tomorrow. Not when things get easier. Not when your circumstances change. Not when you finally get everything figured out.

Today.

There is a reason this Scripture is here. There is a reason we are going through this text right now. In God’s providence, He has brought us to this Word, and through His Word He intends to reprove us, correct us, and exhort us not to harden our hearts.

So where, today, are you hardening your heart?

Where has God spoken clearly, but you continue to resist Him?

Maybe there is a sin you continue to excuse even though you know what God has said.

Maybe there is someone you refuse to forgive even though you know how greatly you have been forgiven in Christ.

Maybe God has been faithful to provide for you again and again, yet you are consumed with worry because you do not believe He will provide this time.

Maybe you know what obedience looks like, but you keep putting it off.

Maybe you have heard the gospel over and over again. You know who Christ is. You know what He has done. You know that He calls you to repent and believe, but every time you hear His voice you tell yourself, “Later.”

Church, be careful with later.

Every time we hear the Word of God, we are responsible for what we do with it.

“Today, if you hear his voice, do not harden your hearts.”

SO how do we make sure that we do not Harden our hearts, the Author will go on to tell us to Guard our hearts by holding fast to Christ.

Gaurd your heart by holding fast to Christ. (12-19)

The Author is going to give us three ways that we can do this.

1. Take Care of Your Heart — v. 12 Watch for unbelief within yourself. To battle unbelief and guard our hearts, we must be vigilant against developing an evil and unbelieving heart.

The wilderness generation failed to trust God despite witnessing His power. They saw His works for forty years, yet when trials came, they continually doubted His character and His promises.

These Christians were facing a similar temptation. They had received the testimony of the risen Christ. They had heard the gospel. They had experienced the blessings of being among the people of God. Yet in the midst of the trials they were facing, they too could be tempted to doubt God’s character and His promises.

And church, so can we.

That is why the author says, “Take care.”

Pay attention. Watch yourself. Do not become careless with your heart. We have to be vigilant about the unbelief that can begin growing within us.

Caring for our hearts requires intentional practices that help guard us from spiritual damage. One of the ways we do this is by cultivating protective practices in our lives.

When we take our thoughts captive and bring them into obedience to Christ (2 Corinthians 10:5), we are guarding our hearts.

When we put the Word of God into our minds and fill our hearts and our time with Scripture, we are guarding our hearts.

When doubts about God’s goodness begin to creep in, we remind ourselves of what God has already revealed about Himself.

When our circumstances tell us that God has forgotten us, we go back to His promises.

When temptation tells us that sin will satisfy us, we answer it with the truth of God’s Word.

But guarding our hearts also means that we have to pay attention to the things that are hardening our hearts.

Anger, bitterness, fear, pride, and unrepentant sin do not simply sit harmlessly in our lives. If we allow them to remain, they begin shaping the way we see God, the way we hear His Word, and the way we respond to other people.

We actually saw this with the wilderness generation.

They allowed fear to become greater than God’s promises. They allowed their desires to become greater than God’s provision. They allowed their frustration to become greater than their remembrance of God’s faithfulness. Eventually, they could witness the works of God and still refuse to trust Him.

Church, we cannot continually feed bitterness and expect our hearts to remain soft.

We cannot continually entertain temptation and expect sin to have no effect on us.

We cannot continually feed our fears while starving ourselves of God’s promises and wonder why we struggle to trust Him.

So we reinforce the defenses of our hearts through prayer, through Scripture, through repentance, and, as we are going to see in the next verse, through the accountability and exhortation of other believers.

But there is another side to guarding our hearts. We are not only trying to keep sinful influences out. We want to maintain a heart that remains responsive to God.

We want a heart that, when the Word of God confronts us, says, “Lord, You are right.”

When Scripture exposes our sin, we repent.

When God’s Word corrects our thinking, we submit our thinking to His Word.

When His promises confront our fears, we choose to believe His promises.

That is a soft heart. It is a humble heart that remains open and responsive to the Word of God rather than continually resisting it.

And this is part of what it means to take care of our hearts.

We do not wait until our hearts have become hardened to start fighting unbelief. We guard them now. We fill them with the Word. We bring our fears, anger, bitterness, and temptations before the Lord in prayer. We repent quickly when sin is exposed.

We guard our hearts today so that the deceitfulness of sin does not slowly harden them tomorrow.

And notice that the author does not leave us to do this alone.

He immediately moves from “Take care” in verse 12 to “exhort one another” in verse 13.

2. Exhort One Another — vv. 13–15 Help one another fight the deceitfulness of sin.

The way that we do this is that we exhort one another.

This is preventative work within the community of believers that helps us battle sin’s deceptive power. This practice isn’t optional or occasional. It is a sustained commitment to mutual accountability within a community of believers.

And church, this is another reason why we should be members of a local church.

You cannot obey the “one another” commands of Scripture by yourself. God has not designed the Christian life to be lived in isolation. We need brothers and sisters who know us, who worship alongside us, who pray for us, and who love us enough to speak truth into our lives.

Because notice what the author says:

“But exhort one another every day, as long as it is called ‘today,’ that none of you may be hardened by the deceitfulness of sin.”

Sin is deceitful.

Sin rarely walks into your life and announces what it intends to do to you.

It does not say, “I am here to destroy your marriage.”

It does not say, “I am here to ruin your testimony.”

It does not say, “I am here to pull you away from Christ.”

It deceives.

There can be a subtle, gradual pulling of a person away from God without them even being fully aware of what is happening. And because sin is deceitful, sometimes other believers can see what is happening in us before we can see it ourselves.

That is when we come alongside one another and speak truth into each other’s lives before that hardening becomes entrenched.

Sometimes we need someone who loves us enough to say, “Brother, I see what is happening here.”

Sometimes we need someone to remind us, “You are not thinking biblically about this.”

Sometimes we need someone to tell us, “You are allowing bitterness to take root.”

Sometimes we need someone to remind us of God’s faithfulness because our circumstances have caused us to forget it.

And sometimes we need to be that person for someone else.

This is how God has designed His church.

We exhort one another by stirring one another up toward love and good works (Hebrews 10:24).

We encourage one another, both personally and in the regular gathering of the church (Hebrews 10:25).

We admonish the idle, encourage the fainthearted, and help the weak (1 Thessalonians 5:14).

We teach and admonish one another through the Word of God (Colossians 3:16).

We bear one another’s burdens (Galatians 6:2).

We help one another lose a complaining heart and replace it with a heart filled with gratitude and grace.

And all of this matters because verse 14 tells us:

“For we have come to share in Christ, if indeed we hold our original confidence firm to the end.”

Believers share in Christ, and one of the evidences that we truly belong to Christ is that we hold our original confidence firm to the end.

And one of the means God uses to keep His people holding fast is His people.

That changes the way we think about church.

I need the church because I need people who will point me back to Christ.

You need the church because you need people who will point you back to Christ.

And the people sitting around you need you to point them back to Christ.

The repeated call, “Today, if you hear his voice, do not harden your hearts,” emphasizes that the moment for response is now, not later.

There is urgency here.

Do not wait until someone has completely walked away before you care about their soul.

Do not wait until bitterness has consumed them.

Do not wait until the marriage has fallen apart.

Do not wait until the sin has become deeply rooted.

Exhort one another today.

And as believers see the Day approaching, this becomes even more important. Hebrews 10:24–25 tells us to consider how to stir one another up to love and good works, “not neglecting to meet together, as is the habit of some, but encouraging one another, and all the more as you see the Day drawing near.”

Church, exhortation is not merely a nice thing Christians do for one another. It is one of the means God uses to preserve His people in faithfulness. We have to build this into our church culture, that takes time, commitment and vulnerability.

So take care of your own heart.

But do not stop there.

Help your brothers and sisters guard theirs.

3. Hold Fast to Christ — vv. 14–19 Continue believing Christ to the end, unlike the wilderness generation.

Our holding fast to Christ does not cause us to become participants in Christ. It demonstrates the reality of our participation in Christ.

The author says in verse 14:

“For we have come to share in Christ, if indeed we hold our original confidence firm to the end.”

Notice the language. “We have come to share in Christ.”

Perseverance is evidence of genuine faith. It is not the meritorious basis of our union with Christ. We do not hold fast long enough, believe hard enough, or obey well enough and finally earn a place in Christ.

We hold fast because by faith we belong to Christ.

And that is why the author brings us back once again to the wilderness generation in verses 16–19.

Look at the questions the author begins asking.

“Who were those who heard and yet rebelled?”

Well, it was not a group of people who knew nothing about God. It was not the Egyptians. It was not the Canaanites.

“Was it not all those who left Egypt led by Moses?”

These were the people God had rescued.

These were the people who had been covered by the blood of the Passover lamb. These were the people God brought out of slavery. These were the people who walked through the Red Sea. These were the people who ate the manna and drank the water God provided.

They heard, and yet they rebelled.

Then he asks, “And with whom was he provoked for forty years?”

“Was it not with those who sinned, whose bodies fell in the wilderness?”

Think about the tragedy of that statement.

They came out of Egypt, but they never entered Canaan.

They experienced deliverance from Egypt. They experienced the blessings of being among God’s covenant people. They saw His mighty works. Yet an entire generation died in the wilderness because they refused to believe God.

Then the author asks one final question:

“And to whom did he swear that they would not enter his rest, but to those who were disobedient?”

And then verse 19 gives us the diagnosis:

“So we see that they were unable to enter because of unbelief.”

Notice how the author brings unbelief and disobedience together.

Verse 18 says they were disobedient.

Verse 19 says they were unbelieving.

Those are not two unrelated problems.

Their disobedience flowed from their unbelief.

They did not obey God because they did not trust God.

God said, “I will give you the land.”

They said, “There are giants there.”

God said, “I will be with you.”

They said, “We are going to die.”

God said, “Go.”

They said, “We cannot.”

Their disobedience revealed what they actually believed about God.

And church, ours does too.

We can say that we believe God is good. We can say that we believe His Word is true. We can say that we believe His commands are for our good.

But what happens when obedience costs us something?

What happens when His Word confronts something we want?

What happens when His promises seem to contradict what we see happening around us?

Faith does not merely say that God is trustworthy. Faith trusts Him enough to obey Him.

It is easy for us to sit here thousands of years later and say, “How could they do that? How could they see the Red Sea split and still doubt God? How could they eat manna from heaven and still complain? How could they see the glory of God and still refuse to trust Him?”

But how many times has God been faithful to us?

How many prayers has He answered?

How many times has He provided?

How many times have we opened His Word and seen His promises?

And yet when the next trial comes, how quickly do we begin to wonder whether God is really going to be faithful this time?

The wilderness generation is not here so that we can look down on them.

They are here as a warning because we have the same problem they had.

We have unbelieving hearts.

And church, this is where we have to understand the gospel.

Because if the message of this passage is simply, “Look at Israel and try harder than they did,” then every one of us is in trouble.

We have all sinned and fallen short of the glory of God.

We have all missed the mark.

So our hope cannot be that we have been more faithful than the wilderness generation.

Our hope is that Jesus Christ has been faithful for us.

Where Israel failed in the wilderness, Christ remained faithful in the wilderness.

Israel was tested and grumbled against God.

Jesus was tested and trusted His Father.

Israel hungered and complained about God’s provision.

Jesus hungered for forty days and declared, “Man shall not live by bread alone, but by every word that comes from the mouth of God.”

Israel continually questioned whether God was truly with them.

Jesus entrusted Himself completely to His Father.

Where Adam failed, where Israel failed, and where you and I have failed, Jesus remained faithful.

And then this faithful Son went to the cross for faithless sinners.

The One who never rebelled bore the judgment of rebels.

The One who never hardened His heart bore the wrath deserved by those with hardened hearts.

The One who perfectly obeyed the Father took upon Himself the punishment of the disobedient.

Jesus died in our place for our sins, and on the third day He rose from the grave.

And now the call of the gospel is not, “Clean yourself up and prove that you are worthy to enter God’s rest.”

The call is:

Repent and believe in Jesus Christ.

Come to the faithful Son.

Trust in His finished work.

Rest in His righteousness rather than your own.

And hold fast to Him.

Because the rest that Israel ultimately needed is the same rest that we need. It was never merely about ending their wandering in the wilderness and settling in Canaan.

There is a rest that God's people enter through faith in Christ, and there is a final rest that awaits us when Christ brings us home.

The way into God's rest is not through our works, our goodness, or our ability to make ourselves right with God. We enter by faith in Christ and His finished work.

The warning before us today is clear.

Do not hear His voice and harden your heart.

Do not look at the faithfulness of Christ and turn away in unbelief.

Hold fast to Christ.

When you are tempted.

When you suffer,

When you doubt,

When following Christ costs you something,

When the world offers you an easier road,

And when you stumble and sin, do not run away from Christ.

Run to Christ abnd hold him fast

Because our confidence is not ultimately in the strength of our grip upon Him.

Our confidence is in the strength of the Savior to whom we cling.

So church, today, if you hear His voice, do not harden your heart.

Take care of your heart.

Exhort one another.

And hold fast to Christ to the end and do not harden your hearts.

Maybe yesterday you did harden your heart.

Maybe yesterday you ignored His Word.

Maybe yesterday you gave in to that temptation again.

Maybe yesterday you allowed bitterness to grow.

Maybe yesterday you doubted His goodness.

Maybe you have spent years resisting what you know God has said.

But the Word of God comes to you today.

And if you hear His voice today, do not harden your heart.

Repent today, Believe today, Forgive today, Obey today, Encourage your brother or sister today.

Turn from the sin that has been deceiving you today.

And hold fast to Christ today.

Because none of us is promised tomorrow.

If you have never trusted Christ, today, hear His voice. Turn from your sin and come to the faithful Son who died and rose again to save sinners.

And Christian, if you have been wandering, today, hear His voice.

Come back to the One who has been faithful even when you have not.

Take care of your heart.

Exhort one another.

Hold fast to Christ.

And then tomorrow, if the Lord gives us another day, we will wake up and do it again.

We will take care.

We will encourage one another.

We will hold fast.

Until there are no more trials to endure, no more temptations to fight, no more unbelief to battle, and no more danger of drifting away.

Until our faith becomes sight.

Until we enter that final rest.

Until we see the Christ to whom we have been holding fast face to face.

Today, if you hear His voice, do not harden your heart.