True Discipleship: A Matter of the Heart
Passage: Luke 6:43–6:49
True Discipleship: A Matter of the Heart
What does it mean to truly follow Jesus? As you think about the culture of our day, this is a question we need to address with more clarity. What does it mean to follow Jesus? The need for clarity arises from two contemporary challenges – both of which can easily highjack our thinking and therefore derail our discipleship. The first challenge is perhaps the most obvious. It’s the challenge of secularism, which defines life without any reference to God or religious teaching. Think of our own culture, where a full 26% of Americans now claim no religious affiliation. That’s a dramatic increase over the last three decades, and that’s the world we live in. Secularism demands that we have a clear answer on what it means to be a Christian, what it means to follow Jesus.
But there is a second challenge facing the church, and considering our context in the Bible belt, this challenge is arguably even more pressing for our congregation. It’s the challenge of nominalism, or more specifically, nominal Christianity. This is Christianity in name only – that is, people who claim the label of Christian, but don’t actually practice the faith. They aren’t committed to Christ and his church, and they don’t really have any intention of building their lives on Scriptural teaching. Think of the label I used just a moment ago – the Bible belt. What is that label describing? Basically, it is describing nominal Christianity – this wide swath of people who claim the name Christian but don’t actually practice the faith.
But here’s the uncomfortable question, brothers and sisters. Where does nominalism come from? How does it come into being and take root in a culture? The answer, if we’re honest, lies with the church. Nominal Christianity takes root wherever the church fails to clearly answer the question, “What does it mean to follow Jesus?” As clarity on that question goes down, nominalism goes up.
And that’s why I say we need more clarity on what it means to follow Jesus. By all means, we need to be aware of the challenge of secularism, which will only increase in the days ahead. But just as importantly, we need to be clear that following Jesus cannot be pursued in name only. If secularism challenges the church from the outside, then nominalism challenges the church from within. And therefore, we need to be clear, brothers and sisters, on what it means to truly follow Jesus.
And there is no one better positioned to help with this challenge than the Lord Jesus Christ. One of the many blessings of preaching through the Gospels is that we are reminded of crystal-clear precision Jesus uses to define discipleship. For Jesus, there is nothing so serious, nothing so urgent, nothing so necessary as the call to discipleship. This thing we call the Christian life is no small matter to Jesus. He speaks clearly, and that means there is no one better than Jesus to help us confront the challenge of Christianity in name only.
And our passage this morning is a powerful example of how Jesus does this. You’ll notice in your Bibles that our text is the conclusion to Jesus’ Sermon on the Plain. The sermon began back in v20, and it represents Jesus’ call to discipleship. And as we’ve seen, that call is radical. Jesus turns the ways of the world upside down. True blessing, Jesus says in v20, is found in dependence on God, even when that dependence is costly. Love, Jesus reminds us in v27, is to be expressed not just toward those who love you, but toward your enemies as well. Mercy, Jesus teaches in v36, leads us to give what we’ve first received. And truly caring for others, Jesus says in v41, begins with rejecting self-righteousness in favor of honestly addressing the sins in our own lives.
Do you hear how relentless Jesus is in clarifying what it means to follow him? He’s answering both of those challenges we face. When you listen to Jesus’ teaching, you quickly realize there’s no way to understand life apart from God, but more importantly for us this morning, there’s also no room for being a Christian in name only. Jesus demands that your entire life – from your thinking to your pursuits to your relationships – everything, must be defined in relationship to him and his Word.
And this last section of Jesus’ sermon really drives that emphasis home. Here in these closing verses, Jesus gives us two marks of true discipleship, both of which help us answer the question – “What does it mean to follow Jesus?”
True Discipleship Begins with Heart Transformation
Let’s look at these two marks from Jesus’ teaching. The first comes in vv43-45 – True Discipleship Begins with Heart Transformation. Jesus does something a bit unique in this section of his sermon. He puts his illustration first before he gives the principle. Notice the illustration he uses. It’s a simple picture of a powerful point. V43 – “For no good tree bears bad fruit, nor again does a bad tree bear good fruit, for each tree is known by its own fruit.” Now, Jesus’ point is straightforward. Fruit corresponds to nature, or we might even say, fruit reveals nature. Healthy trees bear good fruit, while unhealthy trees bear bad fruit. Once the fruit is seen, there’s no way to hide the tree’s nature.
In fact, notice the last line of v44, where Jesus makes just this point – “For figs are not gathered from thorn bushes, nor are grapes picked from a bramble bush.” Again, fruit reveals nature, and you can’t break that connection. You can have the best gardening practices in the world, with the most powerful fertilizer known to man, and you will never get grapes from thorn bushes. Why? Because a plant’s nature determines its fruit. Fruit reveals nature.
Now, in the context of Jesus’ sermon, this is the Lord’s final rebuke to the hypocrite of v42. This is why self-righteous hypocrisy is ultimately foolish – because after awhile, you can’t fake it anymore. At some point, the fruit of your life will reveal the true nature of your heart.
And indeed, that is where Jesus goes in v45. He’s given his illustration, and now he applies it to our hearts. Notice the Lord’s very strong words, v45 – “The good person out of the good treasure of his heart produces good, and the evil person out of the evil treasure produces evil, for out of the abundance of the heart his mouth speaks.” Again, Jesus is straightforward. Just as fruit reveals a plant’s nature, so also our actions reveal the nature of our hearts. There is a connection between the two, just like the connection between a tree’s root and its fruit. A person’s life reveals the nature of his or her heat.
Now, we need to pause here and remind ourselves of what Jesus means when he speaks of the heart. In Scripture, the heart represents the control center of life. The heart is the place of our affections and our desires, and those affections and desires shape what we live for. In fact, Jesus’ image here in v45 is actually summarizing this biblical idea. Jesus envisions the heart like a treasure chest – that’s what Jesus means by good treasure and evil treasure. He’s not talking about treasure out in the world that we’re chasing after. No, he’s talking about the treasure we’ve stored up in our hearts. The heart is like a treasure chest where we keep what is precious to us. And from that store of treasure, we act. We bear fruit, and that fruit reveals what kind of heart we have. The good person, whose heart is good, produces good, while the evil person produces what’s evil. Again, it’s a simple but radical point. The heart is the seat of human life, and therefore, how we live reveals what’s inside.
Before we move on, brothers and sisters, I hope you see here how vital it is that we guard what enters our hearts. It’s now sadly popular to kind of mockingly cite Proverbs 4.23 – “Guard your heart, for it is wellspring of life.” If you hear that verse at all these days, it is almost surely with a sarcastic intent, as though the Scripture is merely quaint or cute.
But it’s true, brothers and sisters, that we should be vigilant as to what enters our minds and then flows to our hearts. Out of the overflow of the heart, the mouth speaks, Jesus will say. What we pursue, love, and cherish matters – far more than we realize. What we store up in our hearts shapes how we live.
I’ll ask you – what are you storing up? What are you treasuring, prizing, and pursuing? Listen, there is a reason the first step of our mission statement as a church is that word treasure – it’s because of passages like Luke 6. What you treasure shapes how you live. What are you treasuring? What is your heart pursuing? Answer that question and you’ll very likely find what is shaping the trajectory of your life, day in and day out.
But at this point, we need to deal with one of the hard realities of Jesus’ teaching. Remember, I said there is no one better than Jesus to confront the challenge of Christianity in name only, and here’s a prime example of that. The hard reality is this – every one of us comes into this world with a bad, evil heart. By nature, each one of us is an evil person who produces evil. Think of what Paul says in Ephesians 2 – that we come into this world dead in our trespasses and sins. That is our nature – our hearts are dead, cold, and lifeless. If we use Jesus’ analogy of a tree, then each person has rotten roots that cannot, by nature, bear good fruit.
Paul and Jesus are talking about the same reality. It’s the reality of human depravity, or we could say our sin nature. By nature, we are depraved, and therefore, if left to ourselves, the fruit of our lives will always be evil. This is key, brothers and sisters, to understanding Jesus’ teaching. V45 is not telling us that there are two options before us – good and evil – and therefore, you’d better make the right decision to be a good person. No, that’s not Jesus’ point at all.
Rather, Jesus’ point is for us to recognize that following him – what we call discipleship – following Jesus requires more than outward behavioral change. Following Jesus requires a transformation of the heart. To be Jesus’ disciple, you need a new nature. You need a new heart. You need life infused into the roots of your soul, and only then will you bear good fruit.
If you’re not a Christian this morning – if you have not repented of your sins and trusted in Jesus Christ – I hope you see here the truth of what it means to follow Jesus. Being a Christian can never be reduced to simply doing more good deeds. That’s like a farmer who goes out every morning and staples apples to bunch of oak trees. Has that farmer made those oaks into apple trees? Has he changed their nature? No, of course not, and to think that he has is silly.
But think of how often we make that same mistake when it comes to Christianity. We think, “Well, if I just add enough good deeds, enough ‘good’ fruit to my life, then I’ll be a Christian.” But friend, that no more makes you a Christian than stapling fruit makes the oak an apple tree. Christianity is not about behavior modification. It’s not about adding good deeds on the outside. Christianity is a matter of the heart.
This is why becoming a Christian is referred to as conversion. Something changes – not just your deeds, but the core of who you are. Listen, it is essential that we think clearly on this point. Members of Midtown Baptist – this is monumentally important for the life of our church. We must think and speak clearly about conversion. We must get this question right. What is the first step of discipleship? The first step, as Jesus alludes to here in v45 – the first step is what the Bible calls regeneration. Conversion begins not with our decision, but with God’s. By grace, God gives dead sinners like us new natures. He makes us alive. He changes our hearts. Do you see the necessity? It’s a work only God can do. God, by his grace, removes our dead, lifeless hearts that bear only bad fruit, and God gives us new hearts. He infuses life into the roots of our soul, and only then do our lives begin to bear good fruit.
If we don’t keep this truth in view, we risk confusing both ourselves and others on what it means to be a Christian. If we don’t keep this truth in view, then we will perpetuate the plague of nominal Christianity – that you can be a Christian in name only. Being a Christian is not about adding good works to your life, like the farmer who staples apples on the oak tree. Being a Christian is actually a miracle of grace. Following Christ begins with God causing you to be born again, with God giving you a new heart that bears fruit in keeping with repentance.
Now, even as we remind ourselves of this key truth, there is perhaps another question lurking in our minds. I know it’s lurking in my mind. And the question is this – if I am a Christian, then why is there still bad fruit in my life? If God has given me a new heart, then why are there still evil, sinful deeds present in my life? Have any of you asked that question before, maybe even this morning? It’s the question of how to understand our remaining sin. If being a Christian means receiving a new heart from God, then why do I still struggle with sin?
Brothers and sisters, this is where we need to remember that as Christians we live in between two ages. Our lives are marked by a tension of living between the already and the not yet of God’s work. On the one hand, I am already a new creation in Christ. The old has gone; the new has come. As a Christian, I am no longer a slave to sin, and even my struggle against sin demonstrates that I am free, that I am alive. As one old preacher said, a dead person doesn’t struggle, so even the struggle against sin is an evidence of God’s grace in my heart. I am already a new creation in Christ Jesus.
And on the other hand, I am not yet glorified with Christ in the new heavens and new earth. I am not yet reigning with Christ in the New Jerusalem, and therefore, I still have the last vestiges of my old sin nature that wage war against the new man God has created me to be.
But this is key. That struggle against sin is not a sign that God’s work has failed. No, the struggle against sin is a sign that God’s work is ongoing. It is happening, even now, as I fight against sin. Our fight against sin is part of the good fruit Jesus speaks of here in v45. When I confess my sin, I bear the fruit of the Spirit’s work in my heart. When I memorize Scripture to fight sin, I bear the fruit of the Spirit’s work in my heart. When I labor to grow in holiness – sometimes taking two steps back for ever one step forward – when I labor, I bear the fruit of God’s work in my heart.
And that means, brothers and sisters, that Jesus’ teaching here in v45 should actually encourage us to fight all the more for the holiness without which no one will see the Lord. This is the incredible power of the gospel. Because of God’s work to grant me a new heart, I now have confidence to face the remaining sin in my life. I have hope that though the battle is fierce today, the war is actually over. Christ has won. The tomb is empty. The new creation will come, and that includes in my own heart and life. And armed with that hope, we fight. We labor. We strive to bear the good fruit God calls us to bear.
But it all begins with God’s work in our hearts. That is the first truth Jesus very clearly calls us to see. There is no true discipleship without heart transformation.
True Discipleship Calls for Heartfelt Obedience
And that leads us into the second mark of true discipleship, this time in vv46-49. True Discipleship calls for Heartfelt Obedience. Again, we are confronted with Jesus’ searing clarity in v46. He leaves no room for being a Christian in name only. Listen to the Lord, v46 – “Why do you call me, ‘Lord, Lord’ and not do what I tell you?” Brothers and sisters, do you hear the Lord’s clear authority there? There is no discipleship apart form submission to the lordship of Christ. To be a Christian is to submit, by faith, to Jesus’ Word. And that submission is then demonstrated in a life of increasing obedience.
Now, note carefully that the standard here is not perfect obedience, but rather obedience. And that obedience includes confessing sin, growing in holiness, and continual trust in the gospel. Let’s not make Jesus say more than what he intends here. He’s not saying you must have a track-record of perfect obedience. But let’s also not attempt to make Jesus say less than what he intends. He does insist on obedience to be his disciple.
And remember, brothers and sisters, believing the gospel is the first and foundational step of obeying Christ. Recall Jesus’ words in John 6 – “This is the work of God, that you believe in him whom he has sent.” How do we obey Christ? We believe the gospel message – that we are sinners, and that Christ alone saves us through his sin-atoning death and his death-destroying resurrection. And then, having believed the gospel, we keep believing by God’s grace, and we work out our salvation with fear and trembling, for it is God who works in us both to will and to work for his good pleasure. To follow Christ is to submit to his Word.
And yet, obedience to Christ is a high calling, isn’t it? There is a cost to discipleship, and though we know that Jesus’ commands are not burdensome, there is still a cost to be paid for obedience. Most often, that cost is paid in denying ourselves, but other times, the cost requires that we endure hardship, ridicule, or suffering for the sake of obedience. That’s another of those tensions in the Christian life. Jesus’ commands are not burdensome, and there is a cost to following him.
The Lord Jesus knows this, which is why he paints a compelling picture in vv47-49. Look there with me. Again, Jesus uses imagery, but now he describes two houses – one built on a solid foundation, v47, and one built on sand, v49. Both houses are struck by a flood, but only one stands. The house built on the sand collapses quickly, Jesus says, and the destruction is terrible. But the house built on the solid foundation endures. It stands firm. The waves crash, but the house doesn’t move. Which house would you choose to live in? Of course, you’d pick the house that stands firm! You’d pick the house on the rock! The choice is clear. The wisdom is plain to see.
And that is precisely Jesus’ point. He uses this compelling picture to show us the wisdom of heartfelt obedience to his Word. Life will bring all sorts of storms, and those storms will rage and crash against us. And yet, the life built on the gospel will not fall. The life built on Scripture will stand firm. The life anchored in Jesus’ word will endure. Now, will there be some damage along the way? Will some of the paint be striped from the house? Yes. Might some of the windows break? Very likely. Will the walls even shake or sway at times? Surely. But will that house fall? Never. That is Jesus’ promise, and that is the wisdom of building your life on the gospel. The floods will rage, but the soul that takes refuge in Jesus will stand to the end.
Brothers and sisters, this is why obedience matters in the Christian life. Obedience to Scripture is an expression of faith. When we obey the Bible, we are saying to God, “I trust you, Father, and I trust your Word. I trust you so much that I will build my life on what you have said, and I believe you will save me to the end.” Obedience to Scripture is not about earning God’s favor, so that he pays us back with salvation. No, obedience, rightly considered, is the outworking of faith. I trust God, and therefore, I obey God’s Word.
This is the Christian life. By grace, God has made our hearts new in Christ, and now by faith, we put our new hearts into action to obey God’s Word. Where is the Lord calling you to obey his Word this morning? Is there an area of life where you have been resisting his lordship? Maybe in a relationship, maybe in the realm of personal conduct, maybe in how you go about your work, or maybe in how you use your time and finances. God wants all of you, brothers and sisters, so where is the Lord calling you to obey this morning?
You know, Baptists have historically been known as people of the Book. That is, Baptists stood out for their simple but firm grounding in Scripture. Let’s go back to that, brothers and sisters. Let’s aim for our lives to be marked by a Word-Driven simplicity. What the Bible says, we believe and do and love. Let’s aim to make it clear that we are under the lordship of Christ in his Word. Where is the Lord calling you to obey?
As we close, there is one final piece to Jesus’ teaching that we need to see. It’s from vv47-49, and it has to do with the flood that crashes against the two houses. In the Bible, a flood often represents God’s judgment. Think of Noah and the flood in Genesis 6. The flood was God’s judgment on the earth. And so it is throughout Scripture. Floodwaters are associated with the judgment of God.
When Jesus speaks of the flood crashing against these two houses, he’s not only talking about the trials of life in this world. He’s even more importantly speaking of the judgment of God. That judgment will come, and there is only one way to be saved when the flood rises. And that is to take refuge in Jesus Christ – to believe his gospel, and to hide yourself in him, just like Noah hid in the ark.
And that means that this passage on discipleship ends with an encouragement and with a call. The call is to anyone who has not trusted in Jesus Christ. Your life, right now, is like the house built on sand. When the flood of God’s judgment comes, you won’t stand. Your life will collapse, and you will be separated from God forever. Without Christ, you cannot be saved. Whether you are young or old – whether you’ve heard the gospel once or many times – today is the day, friend, for you to repent of your sin and trust in Christ. Right now, look to Jesus Christ. Believe that he is the Son of God who alone can pay for your sin. Trust him, build your life on him, and be saved. That’s the call of the gospel that ends this passage.
Along with that call, there is also the encouragement of the gospel for those who believe. The house built on the rock survived the flood – praise God. So also, the life built on Christ is saved from the judgment of God. “On Christ the Solid Rock I stand, all other ground is sinking sand.” Brothers and sisters, what a hope we possess in Jesus Christ! What a treasure we’ve been given! Even when our struggle against sin is at its fiercest, we have this hope – that the judgment of God has been poured out on Christ, and therefore, we are saved.
At the end of it all, brothers and sisters, this is true discipleship. It’s being found in Christ, banking our lives on him alone, and rejoicing in the gospel confidence we have in him.
May the Lord make us a church that delights in obedience to Christ, so that the world will see there is no Treasure so great as knowing the Lord Jesus. Amen.