In this message, Pastor Matt warns us of three paths to hard-heartedness;
1. Sin’s deceitfulness
2. We harden our own hearts
3. Unbelief in God’s promises
Introduction: The Series on Rest and Warnings
This is the same text as last week—in fact, next week it will be the same text as well—and we’re going into different aspects of it. Last week we talked about the nature of that rest. This week we’re going to speak about the warnings: the anatomy of apostasy.
Apostasy is just a fancy word for falling away from Jesus Christ. It’s actually the Greek word apostasia. From two weeks ago, we said we were going to take warnings seriously. I haven’t always taken warnings seriously in my life.
There are a lot of signs like this around on various pieces of equipment on my dairy farm where I farmed for many years. There was a sign somewhat like this on our sand manure separator. We use sand for bedding—the cows lay in sand—but it gets in the manure, and this machine separates it out and washes it so we can reuse it. Pretty cool machine.
One day in the morning I was busy at work, and there was a problem with the sand manure separator. I went over there and looked at the problem. I could have just gotten down off the machine and walked around, but I wanted to be fast, so I took a step across it.
This is actually what the machine looks like. It’s from McLanahan—a little bit of an ad in case you want to buy a sand manure separator—but this is what it looks like. It’s all manure-smelling, a big giant spinning auger of death that takes the sand out and washes it down. It was never this clean; this one’s obviously brand new.
As I was stepping across at 6 a.m. Friday morning—soon after my youngest child was born—my foot slipped, and I fell into the spinning manure auger of death. The flighting is smooth up there, but down in the pit is an agitator with spiky things, perfect for grabbing careless farmers, pulling them underneath, crushing them, and drowning them in a smelly pit of doom.
I probably should not have ignored the warning.
Let’s pray. Lord God, as we look at Your Word today, I pray that we would look at the signs of warning and learn from them. In Jesus’ name, amen.
The Central Theme: Guarding the Heart
Perhaps being slightly careless is something I do more than once, but the one from this week you’ll have to wait till it’s less hot in my mind.
The anatomy of apostasy has to do with our hearts, and this is the central theme of the warnings in this section of Scripture. Why would one fall away? Because their heart is evil and unbelieving.
Let’s see all these warnings:
- Hebrews 3:8 – “Do not harden your hearts as in the rebellion, on the day of testing in the wilderness.”
- Hebrews 3:10 – “For forty years… I was provoked with that generation, and I said, ‘They always go astray in their heart; they have not known my ways.'”
- Repeated in Hebrews 3:15 – “Do not harden your hearts as in the day of rebellion.”
- And today again He appoints a certain day, “Today,” saying through David so long afterward (in Psalm 95, written far after the Exodus), “Today, if you hear his voice, do not harden your hearts.”
The main theme here of warning is to watch your heart.
We tend to think about hearts primarily in terms of emotion—like Valentine’s Day, or feeling like the team won the Super Bowl because they had more heart. But in the Bible, and to the Hebrew mind, the heart is the thing that causes us to act in a certain way.
In the Bible, the heart has four aspects:
- It governs our mind—what we think. “Out of the abundance of the heart the mouth speaks.” Genesis 6:5 says God saw that man was wicked, and every intention of the thoughts of his heart was only evil continually.
- It governs our choices and our will. We’ve been talking about Exodus in Sunday school—Pharaoh’s heart was hard, so he didn’t let the people go.
- It governs our affections (emotions)—what we desire or don’t like. We are to love the Lord with our whole heart. Our heart is why we desire pineapple on pizza—or dislike it. When that goes toward desiring sin—things opposed to God—the heart is very important.
- It governs our conscience—how we sense right or wrong.
Why did Israel go wrong? Their hearts were hard—not to listen to God with their mind, will, affections, or conscience.
The promise in the New Covenant in Christ is specific to our hearts. Ezekiel 11:19 says, “I will give them one heart, and a new spirit I will put within them. I will remove the heart of stone from their flesh and give them a heart of flesh.” That is a soft heart.
(If you want to take this as my Valentine’s Day sermon, you can—I’ve already drawn six hearts and will draw more.)
Yet here in Hebrews, we read these warnings written to believers in Jesus Christ, whom he knows have a new heart. But that heart has to be guarded and kept new by watching out for the signs so our hearts don’t fall into the spinning manure auger of smelly death.
In this text, we see three causes of hard-heartedness:
- The deceitfulness of sin.
- We harden our hearts (it’s something we cooperate with).
- Unbelief in God’s promises or God’s goodness.
Cause 1: The Deceitfulness of Sin
Hebrews 3:13 – “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.”
The exhortation here is warning others about the danger of sin so we are not hardened. Our hearts are hardened by the deceitfulness of sin. Sin deceives. It offers us something we think is going to be good for us—whether a higher desire or a fleshly one.
Sin deceives in a lot of ways, like in the Garden of Eden—the serpent deceived Eve with lies: the fruit’s good; you’ll be like God. Sin still today hides itself in things that look good.
These things take on many characters. You might care deeply about the holiness of the church—that’s great. We’re supposed to exhort one another. But you can exhort in a way that puts yourself in the place of God, puts others down, and forgets you can be deceived by the same sin.
There’s a reason Galatians 6:1 says to restore gently, watching yourself lest you be tempted. We can fall into a pharisaical frowning down on people. If I had a fantasy draft as a pastor, I’d pick the drunk before the self-righteous Pharisee.
But don’t forget: sin is deceiving. As soon as you say, “Yeah, the Pharisee,” if you’re the drunk living in sin, you might think, “Well, I’m not so bad after all.” But the sin of drunkenness is incredibly destructive and evil.
You don’t need a good excuse to sin; you just need any excuse if that’s what your heart is leaning toward. Sin deceives in terrible ways. The deceiving sin of drunkenness will drag you to hell just as fast as pharisaical hypocrisy—whether the bait is illicit pleasures or self-righteous gossip, the hook of sin and the angler (the devil) will get you on the same line.
Sin is bad—not surprising—but the danger isn’t the sin itself (Christ’s blood covers any sin; you can be forgiven of anything). The danger is that sin deceives us in a way that hardens us. Sin in our lives is like cholesterol hardening your arteries so blood can’t pump anymore—one day you keel over. Sin hardens us so our hearts become harder toward God. A hard heart is in danger of falling away from the living God.
Our hearts become hard when we are deceived by the lies of sin and rest in sin instead of resting in Christ.
Cause 2: We Harden Our Hearts
Hebrews wants us to see that while we’re not under the old covenant (praise the Lord—the blood of Jesus covers us from every sin), the actions of God’s people under the old covenant serve as warnings.
Hebrews 3:7-10 – “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 fathers put me to the test and saw my works for forty years.'”
Hebrews quotes Psalm 95 (which they know David wrote), but says “the Holy Spirit says” because this warning is present and for you today: “Do not harden your hearts.” It’s something we do.
In Sunday school last week we talked about Pharaoh—he hardened his heart again and again in response to God’s warnings and miracles, until God gave him over so his heart of stone became a heart of steel, and he rushed headlong to his own death in the Red Sea.
Their hearts got hard: “Your fathers put me to the test and saw my works for forty years.” Every time I read it, I’m like, “How could they be so dumb?” They walked through the Red Sea on dry land, yet grumbled: “Oh God, the giants are so bad; we don’t have bread.” A hard heart blinds us to God’s works and builds us up in grumbling instead of thanksgiving.
There are people always looking for something to complain about—they can complain about the wetness of the swimming pool. Seeing God’s works and ignoring them—this is me sometimes, reading about Jesus raising Jairus’s daughter, drinking coffee, mind dull to the miracle. Or singing “In Christ Alone”—how amazing! Lord, give me a soft heart.
Being casual about someone’s testimony of deliverance from alcohol—amazing! Lord, I need a soft heart.
There are 10,000 reasons to praise God every day. It’s easy to look past them. May I never grow cold to Your mighty works in Your Word, in my life, and in the church.
We need to share about God’s goodness, encouraging one another with His miraculous works. Grumbling spreads like a plague—someone starts, then you do: government bad, weather bad, everything bad. We need to be people of thanksgiving; it spreads too.
Pointing to God’s works protects us from hardening our hearts. Open your hearts to God instead of hardening them.
Cause 3: Unbelief in God’s Promises
Hebrews 3:12 – “Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God.”
That’s an evil, unbelieving heart—a heart hardened by the deceitfulness of sin, ignoring God’s works, and not believing God’s promise.
The promise is the believer’s everlasting rest (Ben talked about last week)—far better than milk and honey, better than the promised land. A rest from the weariness of this world—a weary world where four people in a house can get shotgunned down. What horror. But God has a promise for something better.
Believing in that inoculates us, but unbelief hardens us.
Hebrews 3:16-19 – “For who were those who heard and yet rebelled? Was it not all those who left Egypt led by Moses? With whom was he provoked for forty years? Was it not with those whose bodies fell in the wilderness? To whom did he swear that they would not enter his rest, but to those who were disobedient? So we see that they were unable to enter because of unbelief.”
They heard the promise of the promised land (just as we hear the promise of everlasting rest), yet accused God of evil: bringing them to die in the wilderness; “We had it better as slaves.” Unbelief led to sin (idolatry and more), and they did not enter His rest—ultimately because of unbelief.
The gospel is simple: Believe in the Lord Jesus Christ and you will be saved. The promises are yours. No matter how you’ve sinned—no matter the pit you’ve fallen into—believe today, and you will be saved and have that blessed rest away from the traumas of this world. What a promise!
But the warning: If you do not believe, you will not have this rest. Unbelief happens day by day as hearts get hard.
I don’t have the experience of falling away—praise the Lord. But I know guys from Sunday school and Bible college who sang the songs, yet now are hardened atheists. Somewhere their hearts got hard—by the deceitfulness of sin, by hardening their hearts, inattentive one thing after another. The promise isn’t theirs.
Watch out for your heart. Believe in God’s goodness—life may be hard here, but God has good for you. This testing is momentary; His promise is forever.
Hard-heartedness happens through the deceitfulness of sin, hardening our hearts by ignoring God’s works, and not believing His good promises. This is the anatomy of apostasy—falling away is about your heart. Guard it by the power of God and the truth.
The warning sign—like on the sand separator—is not that you go in; it’s so you don’t. Stay away. Follow the sign.
Personal Story and Application: Heed the Warning Today
I didn’t finish my story. There I was—in a moment everything slowed. I saw my six-month-old baby being raised by his mother alone as my leg went into the swirling pit. Somehow my hand grabbed the right spot; my leg was picked up (maybe by an angel). In a moment I was sitting on the other side, breathing deeply, in shock—knowing how close I was to a terrible death.
I’ve thought about it too much; it still gives me shivers.
This is like us so many times. We’ve gotten used to the deceitfulness of sin; our hearts slow to God’s work. This is a wakeup call—a sign. The fact you’re still here, still alive, it’s still “today”—don’t take it for granted.
I got out and thought, “God was graceful to give me another day. Praise the Lord I’m still here. I’m never doing that again.”
Today we hear these warnings. If our hearts have slipped, heed the warning. Soften your hearts. God is still calling you today.
In response:
- Exhort one another today—put away sin. A hard heart is dangerous, caused by the deceitfulness of sin again and again. We often don’t see it ourselves, so be in fellowship—small groups, coffee with a Christian friend: “How are you? Am I out of whack? Am I too close to the spinning auger?”
- Open your heart to God’s work today—wonder at how awesome God is. Sing His praises; see His goodness. Reinforce thanksgiving over grumbling. Practical step: Journal daily—one thing you’re thankful to God for. Guard your heart with thankfulness; there are always more graces than problems.
- Believe God’s promise today—God has good for you. He is good; even His warnings are for your good—so you don’t fall into the vortex of sin and hell. He has better: salvation, hope, day by day.
Today is the day to make the choice. If you’ve been wandering, today choose: “I am soft to God. I repent of my sin. I’ll talk to a friend, the pastor, come after service—today I’ll make that choice.”
We think, “I can sin and repent—it’s fine.” You can be forgiven of any sin. But a hard heart one day stops wanting to repent. That’s the danger.
Today: Do not harden your hearts as in the rebellion. Do not fall into the deceitfulness of sin. Watch your heart. Dedicate your life to Jesus Christ.