The Danger of an Unbelieving Heart (Hebrews 3:7–19)

Introduction

We are continuing our series in the book of Hebrews. Today, we are in Hebrews 3:7-19, looking at the danger of having an unbelieving heart. We’re going to look closely at that.

One day, while working in my office at the homeless shelter, a loud drilling sound came from the hallway. It was a huge sound that filled up the whole floor. I came out to see what was going on. They were installing a new drinking fountain in the hallway, and to install it, they had to cut a large hole in the cement.

I was friends with the maintenance man. His name was David. David gave me this round cylinder of cement he had cut out of the building. Within the cement, he showed me that the drill bit had cut through the rebar. A rebar is a steel bar that runs through a concrete structure to strengthen it. David told me that he had to buy a special drill bit that was a diamond core drill bit. This drillbit was specially made to cut through concrete and rebar.

I brought that cement cylinder into the chapel, and I shared with the guys at the shelter how many of their hearts were hard like this cement, and they needed the special diamond core drill bit of the Holy Spirit to break through their hardened hearts. After chapel, one of the guys came up to me with tears in his eyes, took the cement, and said, “Give me my heart.”

Hardened hearts don’t happen in an instant. They occur over time. Hardened hearts happen as one continues to refuse to trust God, to refuse the hope of the gospel. An unbelieving heart is a dangerous thing.

Even as Christians, we can have times when we doubt God and have an unbelieving heart. How can we guard ourselves against an unbelieving heart? We’ll look at that today in Hebrews 3:7-19.

Scripture Reading

Hebrews 3:7–19 CSB

7 Therefore, as the Holy Spirit says: Today, if you hear his voice, 8 do not harden your hearts as in the rebellion, on the day of testing in the wilderness, 9 where your ancestors tested me, tried me, and saw my works 10 for forty years. Therefore I was provoked to anger with that generation and said, “They always go astray in their hearts, and they have not known my ways.” 11 So I swore in my anger, “They will not enter my rest.” 12 Watch out, brothers and sisters, so that there won’t be in any of you an evil, unbelieving heart that turns away from the living God. 13 But encourage each other daily, while it is still called today, so that none of you is hardened by sin’s deception. 14 For we have become participants in Christ if we hold firmly until the end the reality that we had at the start. 15 As it is said: Today, if you hear his voice, do not harden your hearts as in the rebellion. 16 For who heard and rebelled? Wasn’t it all who came out of Egypt under Moses? 17 With whom was God angry for forty years? Wasn’t it with those who sinned, whose bodies fell in the wilderness? 18 And to whom did he swear that they would not enter his rest, if not to those who disobeyed? 19 So we see that they were unable to enter because of unbelief.

Pray

Hebrews 3:7-19 is like a biblical commentary with a very pastoral tone. If you’re unfamiliar with biblical commentaries, they are books usually written by a biblical scholar who takes Bible verses and comments on them. So, if you have a question about John 3:16, you could look up the verse and read what the scholar said about it. The tone of these commentaries usually depends on the author. If you have a scholarly author, you’ll have a technical response. If you have someone more pastoral, you’ll have more of a pastoral tone. That’s what Hebrews 3:7-19 sounds like.

These verses are a commentary on Psalm 95:7-11 and take a pastoral tone in applying what this psalm means for Christians. The writer of Hebrews loves the Psalms. In Hebrews 1-3, he’s already quoted from 8 Psalms: Psalm 2, 8, 22, 45, 102, 104, 110, and now Psalm 95. [1] So far, Hebrews 1-3 could be titled “Jesus in the Psalms.”

The Hebrews writer tells us that Psalm 95 warns us against hardening our hearts in unbelief. If God is speaking to us today, we must be willing to listen and obey through faith.

That is the first way that we can guard against an unbelieving heart. It is to,

Transition

I. Listen to God’s Voice Today

Hebrews 3:7-11

“Therefore, as the Holy Spirit says:

Today, if you hear his voice,

Do not harden your hearts as in the rebellion

On the day of testing in the wilderness,

Where your ancestors tested me, tried me,

And saw my works for forty years.

Therefore I was provoked to anger with that generation and said,

‘They always go astray in their hearts,

And they have not known my ways.’

So I swore in my anger,

‘They will not enter my rest.’”

When God speaks, his voice demands a response. The Scripture starts by telling us,

A. God is speaking, so do not ignore Him.

Hebrews 3:7–8 tells us, “Today, if you hear his voice, do not harden your hearts,” which is real and practical advice for Christians.

Have you ever gotten advice from someone who starts to tell you all about their experience and then warns you not to do what they did? You might have done this with your kids. You tell them about mistakes you’ve made, and you hope they will hear your example and learn from it so they won’t make the same mistakes.

What do they do? Your kids do what you did as a kid. They think to themselves, “I’m going to do it anyway. It’s not going to happen to me!” And does it happen to them? Yes, it does.

Why is that? Because the truth of consequences is consistent in every generation. Your actions, good or bad, will have consequences. The biblical thing to do is to listen to God’s voice and learn from the actions of others.

The Bible is full of examples for us to learn from. Psalm 95 points to the examples of the Israelites in the wilderness from which we can learn.

The first thing it tells us about the Israelites in the wilderness is that,

1. The Israelites tested God and turned away.

These verses point to a story of Israelite rebellion that we read about in Exodus 17:1-7.

In this chapter, the Israelites have been wandering around the wilderness. God had delivered them from slavery in Egypt, he rescued them from the Egyptian army by parting the Red Sea, and he is leading them through the wilderness.

When you get to the scene in Exodus 17, the people of Israel are frustrated. They’ve been moving from one place to the next according to how God led them, but it’s getting dry. The sun is beating down on them; nothing is around them but sand, rocks, and heat.

You can imagine if you were there with your kids. You're getting thirsty, and your kids are getting thirsty. They say a human can survive about one to two months without food, but the average human can only survive about 3 to 7 days without water. The Israelites are thirsty, and they’re frustrated.

The murmuring starts. It usually begins with a few people complaining to each other. You could picture them saying, “If Moses hadn’t brought us out here, we wouldn’t be in this mess.” They finally get up the courage to speak to Moses. He's their leader, so they start complaining to him.

Hear the frustration they expressed in Exodus 17:2,

Exodus 17:2 CSB

2 So the people complained to Moses, “Give us water to drink.” “Why are you complaining to me?” Moses replied to them. “Why are you testing the Lord?”

There is a point of frustration that you can get to where you question everything in your life, including everything God has done. When you don’t give that frustration to God, you will unload it on anyone and everyone around you.

The frustration the Israelites expressed was a frustration against God. Moses gave that frustration to the Lord, saying these Israelites would rise against him. He says in Exodus 17:4,

Exodus 17:4 CSB

4 Then Moses cried out to the Lord, “What should I do with these people? In a little while they will stone me!”

God doesn’t rebuke Moses. Instead, he gives him a command. “Go ahead of the people and take the elders with you. Take the staff you struck the Nile with in your hand, hit the rock, and water will come out of it.” Moses struck the rock, and water came out for the Israelites to drink.

Moses ended up calling that place Massah and Meribah as a memorial to the Israelites complaining. It was a place where the Israelites wondered if the Lord was with them or not. When the water ran out, their faith ran out.

The second thing we learn is,

2. Their rebellion kept them from God’s rest.

The consequences of the Israelites’ rebellion are shown in Numbers 14:21-23. It says there,

Numbers 14:21–23 CSB

21 Yet as I live and as the whole earth is filled with the Lord’s glory, 22 none of the men who have seen my glory and the signs I performed in Egypt and in the wilderness, and have tested me these ten times and did not obey me, 23 will ever see the land I swore to give their ancestors. None of those who have despised me will see it.

The Israelites failed to have faith in God. As a result, they did not enter into the promised land. They did not enter into God’s rest. The Israelites missed out on the promises of God. They refused to trust God. When you refuse to trust God, you miss out on his promises.

The rest of these verses will expand on Psalm 95:7-11 and encourage us to trust God’s promises. Guarding against an unbelieving heart begins with listening to God’s voice today. We must have a heart that listens to God.

One of the things I love about living in Paradise Hills is that you’re still close enough to the ocean to get the cool ocean breeze. But if I never open my windows in my home, I’ll never experience that breeze. I’ll have the stale air in the house. I need to open the windows to let in the cool air.

In the same way, a heart must be open to hear the voice of God. Open your heart to listen to him.

The second way that we guard against an unbelieving heart is to,

Transition

II. Encourage One Another Daily

Hebrews 3:12-15

Watch out, brothers and sisters,

So that there won’t be in any of you an evil, unbelieving heart

That turns away from the living God.

But encourage each other daily,

While it is still called today,

So that none of you is hardened by sin’s deception.

For we have become participants in Christ

If we hold firmly until the end

The reality that we had at the start.

As it is said:

Today, if you hear his voice,

Do not harden your hearts as in the rebellion.

Hebrews 3 will tell us about the importance of being in a church that encourages one another. It begins by reminding us that,

A. A hardened heart turns away from God.

Before telling us about our need for encouragement, he warns us to watch out. In Hebrews 3:12 it says,

Hebrews 3:12 CSB

12 Watch out, brothers and sisters, so that there won’t be in any of you an evil, unbelieving heart that turns away from the living God.

A heart that resists believing what God has said is described as an evil heart. A wicked heart is rooted in denying God's faithfulness and trustworthiness. Refusing to listen to God is an open door to the enemy's lies in your heart.

Jeremiah said it this way in Jeremiah 17:9,

Jeremiah 17:9 CSB

9 The heart is more deceitful than anything else, and incurable—who can understand it?

Our hearts tend to drift away from the truth of God and from believing God’s faithfulness and promises. With this understanding of the human heart, Hebrews 3:13 has an incredible command for the church to protect our testimony. It says that,

B. Daily encouragement protects against deception.

Hebrews 3:13 says,

Hebrews 3:13 CSB

13 But encourage each other daily, while it is still called today, so that none of you is hardened by sin’s deception.

Did you know that your participation and fellowship in the church is a protection for your soul? The church is a gift from God to his people. We need each other.

Fellowship among God’s people is part of your Christian armor against the world’s deception. Jesus gave his people the gift of fellowship to help strengthen us.

Paul says it this way in 1 Thessalonians 5:11,

1 Thessalonians 5:11 CSB

11 Therefore encourage one another and build each other up as you are already doing.

When you are in fellowship in the church, you have an opportunity to be built up by those around you who are strong in the Lord, and you have a responsibility to build others up through your love for God and your love for others.

In Hebrews 3:13, we’re told as a church to encourage each other, not just on Sundays, but “daily, while it is still called today.”

Spreading discouragement will harm the church, but spreading encouragement in the faithfulness of God and his promises will build up the church. We have a responsibility as a church to build each other up in believing the promises of God.

Faith isn’t just a personal battle. Personal faith is also built up through a godly community. As a church, we lift each other and guard against unbelief together. Surround yourself with people who will build you up in Christ.

We also learn in this text that,

C. True faith holds firm to the end.

In Hebrews 3:14 it says,

Hebrews 3:14 CSB

14 For we have become participants in Christ if we hold firmly until the end the reality that we had at the start.

God’s people in the church are now participants in Christ because of the cross. Your participation in Christ is not only about how you start. It’s also about how you finish.

Hebrews 3:14 is a restatement of Hebrews 3:6, a verse we covered last week. It describes perseverance in the Christian life as evidence of faith. True faith will last.

If someone gives you a gift, the evidence that you have received that gift is that you own it. For instance, If it’s a financial gift, it will be in your bank account.

Salvation is an eternal gift, and if you have received that gift, that gift will be in the account of your life. You will face challenges in your life, but there will still be faith in Jesus through it all.

Let’s walk through Hebrews 3 carefully to understand this.

We’re told to listen to God’s voice.

To learn from the example of the Israelites who did not believe in God’s promises

To encourage one another daily

To guard against an unbelieving heart by being in fellowship with other believers

To persevere to the end in the reality we had at the start

In other words, when I look into my life and see that I’m still holding onto Jesus despite what I am going through, my perseverance of faith is evidence that I have the eternal salvation in Jesus Christ I claimed from the beginning.

Paul describes it this way in Colossians 1:22-23,

Colossians 1:22–23 CSB

22 But now he has reconciled you by his physical body through his death, to present you holy, faultless, and blameless before him— 23 if indeed you remain grounded and steadfast in the faith and are not shifted away from the hope of the gospel that you heard. This gospel has been proclaimed in all creation under heaven, and I, Paul, have become a servant of it.

Perseverance in Jesus Christ is evidence of faith. The Israelites who rebelled showed themselves to be people who were not grounded in faith, who were not steadfast in the faith, and people who were constantly shifted away from faith in God. The evidence of their life showed no faith.

However, if you are grounded and steadfast in Jesus Christ, you will be someone who perseveres and enters into God’s rest. Perseverance does not save you. Only the finished work of Jesus Christ on the cross saves a Christian. But perseverance of faith shows that you were someone in Christ in the first place.

True faith holds firm to the end, not because we are strong, but because Christ is strong to sustain and keep us. If you belong to Jesus, you will endure.

The final way that we can guard against an unbelieving heart is to,

Transition

III. Learn from the Failure of Others

Hebrews 3:16-19

For who heard and rebelled?

Wasn’t if all who came out of Egypt under Moses?

With whom was God angry for forty years?

Wasn’t it with those who sinned,

Whose bodies fell in the wilderness?

And to whom did he swear that they would not enter his rest,

If not to those who disobeyed?

So we see that they were unable to enter

Because of unbelief.

Hebrews 3:16-19 asks a series of questions based on the wandering of the Israelites in the wilderness. Questions are important. Questions require you to think and guide you to the truth. That’s why science is built on questions like, “What causes a disease?,” or, “How do planets move?”. Questions guide you to truth, and Christians need truth.

These verses ask questions about the failure of the Israelites so we can learn from their failure. The questions lead us to several answers. The first answer is that,

A. The Israelites saw God’s works but still doubted.

The question in Hebrews 3:16 says,

Hebrews 3:16 CSB

16 For who heard and rebelled? Wasn’t it all who came out of Egypt under Moses?

It was not enough for the Israelites to be surrounded by God’s work. The Israelites saw the plagues in Egypt, the parting of the Red Sea, and manna from heaven. Yet, even with all of the supernatural activity of God around them, they still doubted God.

It also happened during the ministry of Jesus. Many people saw the sick healed, the demons cast out, and even the dead raised. Yet despite God's supernatural activity, not everyone believed in him.

For instance, after the miracle of feeding the five thousand, Jesus told the people who were looking for him this in John 6:26,

John 6:26 CSB

26 Jesus answered, “Truly I tell you, you are looking for me, not because you saw the signs, but because you ate the loaves and were filled.

The key point of that verse is this: A temporary excitement about godly activity does not lead to lasting faith. Just because you got excited at a church event does not make you a Christian. Christianity is not about being moved during a 90-minute service on a Sunday. Christianity is about an authentic, supernatural transformation by Jesus Christ and walking with him daily.

Your faith requires more than experiences. We want experiences. We pray that God will provide and that he will heal. But experiences do not grow faith. If seeing supernatural experiences grew faith, the Israelites would have been overflowing with faith, but they weren’t. They grew numb to the sight of God’s work around them.

Faith must exist in your life in hard times and in good times. Sometimes, people ask God for things in difficult times because they want God to prove himself to them. That’s what the Israelites were doing.

God wants Christians who will trust him when times are hard. Are you trusting in God today or just waiting for him to prove himself to you?

The second lesson we learn from the Israelites is that,

B. The Israelites' sin led to years of judgment.

Hebrews 3:17 says,

Hebrews 3:17 CSB

17 With whom was God angry for forty years? Wasn’t it with those who sinned, whose bodies fell in the wilderness?

The inevitable result of an unbelieving heart is judgment, and it’s a process. Continuing to refuse to trust God leads to callousness in your soul. Without faith in Jesus, only judgment remains.

Paul talks about this when he describes people who knew God but refused to believe him. He says it this way in Romans 1:21,

Romans 1:21 CSB

21 For though they knew God, they did not glorify him as God or show gratitude. Instead, their thinking became worthless, and their senseless hearts were darkened.

It’s not enough to know about God. It’s not enough to know that he exists or sent his Son. The information must lead to transformation. Knowing about Jesus must become trusting Jesus with your life.

The third lesson we learn from the Israelites is that,

C. The Israelites' unbelief kept them from God’s promise.

In Hebrews 3:18-19 it says,

Hebrews 3:18–19 CSB

18 And to whom did he swear that they would not enter his rest, if not to those who disobeyed? 19 So we see that they were unable to enter because of unbelief.

The story of the Israelites is tragic. God’s activity on the outside surrounded them, but on the inside, their hearts had grown callous in unbelief. They were so close to the promise of God, but they could not enter the promised land because of their unbelief.

God today is still calling people to enter into his rest, which is available to everyone through faith in Christ. The door to his rest is open. His arms are open wide.

It’s not enough to be surrounded by the activity of God. It’s not enough to see other people's faith at church or in your home. Your heart must be open to the work of God in your own life. You must be willing to trust God in the good times and the bad. You must seek to follow Jesus Christ not because you want him to give you an experience. You follow Jesus because he is the Son of God, your Savior who is trustworthy and faithful.

Conclusion

We need to listen to God’s voice and learn from the failures of others. But the takeaway today is not about failure. It’s about the power of a heart that goes on a different path and trusts God no matter what happens in your life.

The hope of the gospel is never discouraging. It’s always encouraging. To guard against an unbelieving heart, remind yourself of the hope of the gospel. If you’re encouraged today, encourage others with the hope that we have in Jesus.

In Jesus Christ, there is peace and rest. Trust Christ fully and rest in him.

Prayer

Last Song

Doxology

Numbers 6:24–26 CSB

24 “May the Lord bless you and protect you; 25 may the Lord make his face shine on you and be gracious to you; 26 may the Lord look with favor on you and give you peace.” ’

Jude 24–25 CSB

24 Now to him who is able to protect you from stumbling and to make you stand in the presence of his glory, without blemish and with great joy, 25 to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, power, and authority before all time, now and forever. Amen.

You are dismissed. Have a great week in the Lord!

Heb 1:5 quotes Ps 2:7; Heb 1:7 quotes Ps 104:4; Heb 1:8-9 quotes Ps 45:6-7; Heb 1:10-12 quotes Ps 102:25-27; Heb 1:13 quotes Ps 110:1; Heb 2:12 quotes Ps 22:22; Heb 3:7-11 quotes Ps 95:7-11.

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Sermon Reflection Questions

What is the main warning presented in Hebrews 3:7- 19 regarding unbelief?

How does the story of the Israelites in the wilderness illustrate the dangers of an unbelieving heart?

What does it mean that hardened hearts develop over time?

How can we listen to God’s voice?

How does the encouragement of fellow believers help guard against an unbelieving heart?