Matthew 15:10-20: The Call to Purity (Pt. 2) - The Heart

Intro

Opening

Let’s jump right in.

Last week we began studying Matthew 15 where Jesus goes toe-to-toe with some Pharisees who had journeyed north for over 80 miles just to try to discredit Jesus and his growing influence.

So they try to trap Jesus in a scandal by publicly asking him, “Why do your disciples break the tradition of the elders by not washing their hands?”

Jesus responded by challenging them back!

“Why do your traditions break the Laws of God?”

He then explains how they love to follow their traditions, the mishna. They loved their traditions so much that they have made them more important than God’s actual written and revealed word.

Last week I shared the story of my birthday gift to my brother. It looked impressive at first, wrapped beautifully in multiple layers and bows, but the gift inside was a single, utterly worthless, frilly, sequined sock from a rival sports team.

That’s exactly what was going on with the Pharisees’ traditions — flashy on the outside, but worthless on the inside.

Jesus then goes on to quote Isaiah in verses 8-9, saying:

Matthew 15:8–9 ESV

8 “ ‘This people honors me with their lips, but their heart is far from me; 9 in vain do they worship me, teaching as doctrines the commandments of men.’ ”

He makes the point crystal clear: when we allow tradition to overshadow the Word of God, we end up in a place where everything we do is ultimately worthless.

It leads us to a point where we think we are following God’s Word when we actually are working against him.

We miss the whole point, just like the Pharisees. And even though they were well known and respected for their teachings, those were the very teachings that were leading them and their followers into false worship.

Jesus’ point here is clear: we can make tradition so important to us that we start to forget that the Word of God is more important than anything else.

And when we do that

We honor God with our lips but not our hearts.

We make void the word of God in order to be able to follow what feels right to us.

And in verse 7 Jesus rightly calls those who do so “hypocrites.”

Main Idea: Now, in verses 10-20, Jesus calls the crowd to hear and understand the point of it all, while also calling his disciples to reject the broken priorities of the Pharisees.

True defilement, and it’s opposite — true purity — doesn’t come from the external actions, but from within our hearts.

And the only thing that can bring true transformation is a new heart: a renewal from a heart of stone to a heart of flesh.

Jesus offers this to those who are willing to hear and understand. Let’s see if we are one of them. (Psalm 51:10; Luke 6:45; John 10:27; Matthew 15:10–11; Mark 7:6–8)

So let’s begin at verse 10.

I. The King’s Call to the Crowds: “Hear and Understand” (Matthew 15:10–11)

Key Ideas:

Hear and Understand

Here in verse 10 we’re told that Jesus has turned away from talking to the Pharisees, and turned to now address all the crowds who were there.

And he begins His teaching with two words of instruction for his listeners “Hear and understand” (Matthew 15:10–11).

These were people who, like many of us, were full of traditions that were obscuring the truth.

And those traditions were taught to them by people they trusted and liked hearing, but the whole time, those traditions were like a pair of glasses being put over their eyes to make them view the world in a broken way.

So Jesus turns to the crowds, calling them to take off the glasses they had been taught to wear by all the teachers they liked to listen to.

And instead, He called them to start listening to him.

Hear

I want you to think about the first thing you ever did to begin engaging with Jesus.

Before you prayed a prayer, before you called upon the name of the LORD, before anything else, what did you do?

You heard.

You may have heard audibly,

Through someone teaching the things of God to you in love and faithfulness.

Whether it be a parent or grandparent, a brother or sister, a son or daughter, a friend or coworker, or a faithful pastor.

You may have heard inaudibly,

Through the reading of the Word of God or the reading of the faithful writings of a dear brother or sister in Christ.

However it happened, the first step of your faith that you were involved in was hearing.

So Jesus’ call to hear is not something foreign to us.

But it doesn’t end there. The call is not just to hear, but to understand.

Understand

You see, it isn’t enough to simply hear what Jesus is saying, because hearing only goes so far.

Think about this: every single generation complains about the next generation’s music. Now, if I had you listen to a heavy metal song for you right now. Most of you would probably not understand the words sung and some of you might be considering calling a special meeting to vote on kicking me out.

However, what if I read these lyrics to you?

He washed our sins away

He washed our guilt away

Through the blood of Christ, the Father’s love made known to us

He washed our sins away

He washed our guilt away

Through the blood of God, the riches of his grace for us

Chosen in Christ, only by his grace, for redemption

Full forgiveness lavished upon us

By his Sovereign Love making known to us the mystery of the Son

So that in due time all things unite in Christ

You might think I am reading a new song for worship and want to hear it.

You might rightly recognize that this song is directly based in Ephesians 1.

But if I played it for you, it would be the exact same song.

So, do you see? Hearing is not enough.

It must be accompanied by understanding. This is why Jesus calls everyone to do both.

So to all the people who are gathered he tells them they must hear and understand

Then here in verse 11 we see an important pivot in these verses, from talking about external observances to talking about the heart.

Matthew 15:11 ESV

11 it is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.”

Jesus takes aim at the core of the issue, and the core of the issue is our core, our hearts.

The Heart

Internal Vs. External

We look and sound like the perfect Christians and be more lost than the open pagans down the street. At least they recognize they don’t worship YHWH.

As

Matthew 15:8–11 ESV

8 “ ‘This people honors me with their lips, but their heart is far from me; 9 in vain do they worship me, teaching as doctrines the commandments of men.’ ” 10 And he called the people to him and said to them, “Hear and understand: 11 it is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.”

It is not what enters the mouth that defiles a person (breaking of a tradition), but what exits the mouth from the heart (the sinfulness of our desires) (v. 11).

The big issue of purity is not whether we observe the outward traditions and rituals that we are used to, but RATHER if our hearts are pure.

When we focus on the external expressions of purity and corruption we miss the greater issue: the sinful thoughts and actions that flow from a corrupted heart.

And this is not about your heart “being in the right place”

This isn’t saying it doesn’t matter what you do so long as your feel like you’re glorifying God with your heart.

Jesus points to God’s Word as what we should be following with our very desires

The Hebrew concept of the heart goes far deeper than feelings or thoughts, it is considered to be the seat where all desires are formed.

So we will see if our hearts are corrupted when look at what our desires are truly aimed at.

If I am being really honest with myself, do my desires stem from wanting to glorify God through obedience to his word, or do they stem from desires to get back to my comforts and my preferences?

Because if my desires are tinged at all with self-preference, they are corrupted with sin and Jesus takes all sin seriously because it is deathly serious, even the sins that were deemed acceptable by the culture I grew up in.

A good diagnostic question here is “What causes my heart more distress? Seeing someone misrepresent God - seeing someone be satisfied with just a surface Christianity - or am I more distressed by someone questioning the way we have always done things?

Jesus covered the same concept using a different body part in chapter 6 during his sermon on the mount.

22 “The eye is the lamp of the body. So, if your eye is healthy, your whole body will be full of light, 23 but if your eye is bad, your whole body will be full of darkness. If then the light in you is darkness, how great is the darkness!

In other words:

If the good things we do are actually filled with darkness because of our sinful hearts, how great is that darkness!

We must be willing to ask of ourselves, our ministries, our worship, and everything else, “am I seeking God’s glory or the glory days?”

Skipping down a to verse 18 we see Jesus address this problem

Matthew 15:18–19 ESV

18 But what comes out of the mouth proceeds from the heart, and this defiles a person. 19 For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander.

The Source of Sin

Sin comes from the inside to the outside. It comes from the heart. Some biblical authors, like Paul, call it the flesh instead of the heart, but the concept is the same. Sin comes from inside us, it comes from our desires.

Now, there’s a vital biblical concept that we have to be willing to understand because there are many, even Southern Baptist pastors who have taught against it.

We are not sinners because we sin.

We sin because we are sinners.

For some of you this might be causing you to clench up because it goes against all you’ve been taught about sin.

You may have been taught a form of Pelagianism, an ancient teaching that has regularly been condemned by Christians and yet sees resurgences every few generations.

Pelagianism teaches that every human is born sinless and has the potential to live a completely sinless life. Essentially, humanity is inherently good, and could, in theory, save themselves.

Many people who have followed this teaching have claimed to be sinless for their whole lives.

It’s an appealing doctrine for a variety of reasons.

But we come across a problem: the Bible doesn’t teach it.

The Bible teaches that we sin because, ever since our first parents sinned in the Garden of Eden, it is now part of our DNA.

In Genesis 3 all of humanity and the very earth is put under a curse because of our first father, Adam.

In Ps 51 David cries out:

Psalm 51:5 ESV

5 Behold, I was brought forth in iniquity, and in sin did my mother conceive me.

This isn’t about the act that brought him to conception.

David is lamenting about the depths of his sin! Since before he took his first breath he was beset with sin!

He didn’t become a sinner when he started committing sinful actions. He started committing sinful actions because he was already a sinner.

Paul speaks to the reality of sin being a condition of all humans who were given life through an earthly father because of our first earthly father’s sin in Romans 5

Romans 5:12 ESV

12 Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because all sinned

He prefaces this in Romans 3 by ensuring we recognize:

Romans 3:23 ESV

23 all have sinned and fall short of the glory of God,

The Apostle John takes this even further and says that we’re lying to ourselves and, even worse, making God a liar if we say we are sinless.

1 John 1:8–10 ESV

8 If we say we have no sin, we deceive ourselves, and the truth is not in us… 10 If we say we have not sinned, we make him a liar, and his word is not in us.

And again in Romans, the Apostle Paul makes clear that even though he wants to do what is good, he keeps finding himself acting in sin!

Romans 7:15–25 ESV

15 For I do not understand my own actions. For I do not do what I want, but I do the very thing I hate. 16 Now if I do what I do not want, I agree with the law, that it is good. 17 So now it is no longer I who do it, but sin that dwells within me. 18 For I know that nothing good dwells in me, that is, in my flesh. For I have the desire to do what is right, but not the ability to carry it out. 19 For I do not do the good I want, but the evil I do not want is what I keep on doing. 20 Now if I do what I do not want, it is no longer I who do it, but sin that dwells within me. 21 So I find it to be a law that when I want to do right, evil lies close at hand. 22 For I delight in the law of God, in my inner being, 23 but I see in my members another law waging war against the law of my mind and making me captive to the law of sin that dwells in my members. 24 Wretched man that I am! Who will deliver me from this body of death? 25 Thanks be to God through Jesus Christ our Lord! So then, I myself serve the law of God with my mind, but with my flesh I serve the law of sin.

James 1:14–15 ESV

14 But each person is tempted when he is lured and enticed by his own desire. 15 Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death.

Key Idea:

We need a new heart that is not bound by sin. We do not need to blindly make ourselves feel better by observing external traditions and human ideas. (Luke 6:45; Psalm 51:10)

Luke 6:45 ESV

45 The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks.

Psalm 51:10 ESV

10 Create in me a clean heart, O God, and renew a right spirit within me.

Application:

Salvation History: Christ calls us to be transformed from the inside out—our true cleanliness is a work of grace, not ritual. (Romans 12:2)

Romans 12:2 ESV

2 Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.

Individual Christian Life:

For those wrestling with sin: turn to God and throw yourself on his mercies. Confess your sin to

For the faithful: Let every act of worship reflect genuine love and commitment, not simply duty and moral law. Let your heart respond to the call of the Gospel.

Parents: Show your children that obedience and worship are matters of the heart.

The Proud: Don’t put your pride in how good you act. Don’t put your pride in the cultural groups you are part of.

We have no room to boast of anything.

Non-Christians: If you feel burdened by tradition, know that Jesus invites you to a new way—a life where you hear His call and experience genuine change.

Singles & the Proud: Cultivate an attitude of humility—recognize that wisdom comes through truly hearing and understanding the gospel, not merely repeating it.

Transition:

Truly hearing and understanding Jesus requires the willingness to then reject the false views on spirituality we once believed.

And this is exactly what happens when the disciples come and talk to Jesus about what he just said.

Matthew 15:10–11 ESV

10 And he called the people to him and said to them, “Hear and understand: 11 it is not what goes into the mouth that defiles a person, but what comes out of the mouth; this defiles a person.”

II. The King’s Call to His Disciples: Ignore False Spirituality

“(12)...the Pharisees were offended...”

Look at Matt 15:12

Matthew 15:12 ESV

12 Then the disciples came and said to him, “Do you know that the Pharisees were offended when they heard this saying?”

Basically, they said, “Hey Jesus, you know the Pharisees were offended by what you said, right? We don’t want to be making enemies here.”

And the word used here for “offended” is skandalizo which is where we get our word “scandalized”

The Pharisees were scandalized by the audacity of Jesus!

And what was the response of the disciples? They implication is that they were more concerned about how the Pharisees viewed them and their teacher than they were about the truth in Jesus’ words.

But Jesus was not concerned with the way people looked at him. He was concerned with glorifying God.

“(13) every plant not planted by God will be rooted up”

Key Idea: Recalling language from earlier in the book (like the parable of the Sower)

“(14)Let them alone”

Ignore them

There are many “spiritual leaders” who are ultimately anti-Gospel. They may appear to be good leaders but in reality they are “blind guides”

“(14)They are blind guides”

Pun

“(15-16)Explain the parable” / “Do you still not understand?”

Peter still doesn’t understand though, so Jesus re

(17-20) Purity is a matter of desire, not action

Matthew 15:17–20 ESV

17 Do you not see that whatever goes into the mouth passes into the stomach and is expelled? 18 But what comes out of the mouth proceeds from the heart, and this defiles a person. 19 For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false witness, slander. 20 These are what defile a person. But to eat with unwashed hands does not defile anyone.”

The Remedy: Heart Renewal Through Christ

Key Idea: Jesus not only exposes the source of defilement but also offers a remedy: a renewed heart that only He can bring through His life, death, and resurrection. (John 3:3; Romans 5:1)

Context: While Jesus makes clear that defilement comes from within, His broader ministry demonstrates that the remedy is found in a transformed life that springs from a heart renewed by the Holy Spirit.

Jesus’ teaching on the heart sets the stage for understanding that true purity is an internal matter—only addressed by a genuine, life‑changing encounter with Him.

Exegesis:

The remedy for a defiled heart is not found in observing man‑made rituals but in surrendering to Christ’s redemptive work. (Matthew 15:18–20)

This teaching underlines the new covenant, where transformation is the work of the Spirit, not the observance of legalistic rules.

Salvation History: Christ’s atoning sacrifice and resurrection ensure that every believer becomes a new creation—old things pass away, and a new heart is given. (2 Corinthians 5:17; Ephesians 2:8–10)

Application:

Non-Christians: The gospel invites you to abandon a life reliant on superficial rules and embrace a deep, personal transformation that only Christ can offer.

Public Life & Order: Societies led by individuals with renewed hearts are better equipped to foster justice, mercy, and true integrity.

Individual Christian Life:

For those wrestling with sin: Embrace daily repentance and rely on the Holy Spirit to cleanse and renew your inner being.

For the faithful: Let your transformed heart be the source of your words and actions, reflecting the true nature of Christ.

For the proud: Recognize that self‑righteousness is empty; only humility before Christ can bring genuine renewal.

Specific Groups:

Older Couples/Widows: Your lives testify to God’s sustaining grace—invite His daily renewal regardless of past routines.

Parents: Build your family around the gospel’s truth, showing that the strength of your home comes from hearts renewed by Christ.

Singles: Prioritize inner transformation over outward appearances—seek relationships and communities that encourage authentic growth.

Suggested Illustration: Think of a heart transplant: a failing heart is replaced with a healthy one, reviving the entire body. In the same way, Christ’s transformative work renews every part of our being, starting deep within our hearts.

Transition to Gospel Connection: “With our hearts exposed and in need of renewal, let us now see how the gospel—through the life, death, and resurrection of Jesus—brings this transformation to reality.”

Gospel Connection: Christ’s Transformative Work

Key Idea: The gospel is the ultimate remedy for a defiled heart. Jesus’ life, death, and resurrection not only expose our inner corruption but also empower us to be made new. (John 3:16; 2 Corinthians 5:17)

Jesus’ call for the crowd to “hear and understand” and His dismissal of the Pharisees’ distractions point us directly to the heart of the gospel—a gospel that transforms us from the inside out. (Romans 5:8; John 10:27)

Romans 5:8 ESV

8 but God shows his love for us in that while we were still sinners, Christ died for us.

John 10:27 ESV

27 My sheep hear my voice, and I know them, and they follow me.

Exegesis & Application:

Salvation History: The gospel has always centered on renewing our inner being, not on external adherence to tradition. (Ephesians 2:8–9)

Ephesians 2:8–9 ESV

8 For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, 9 not a result of works, so that no one may boast.

Non-Christians: No external effort can cleanse your heart; only by repenting and believing the gospel can you experience true, lasting change.

Public Life & Order: When individuals and leaders allow the gospel to transform their hearts, communities flourish with integrity, justice, and mercy.

Individual Christian Life: Let the power of Christ’s resurrection redefine your inner life so that every word and deed flows from a heart made new.

Biblical Cross‑References: (John 3:3; 2 Corinthians 5:17; Romans 5:1; Psalm 51:10; Luke 6:45)

Transition: “Embracing the gospel means accepting Jesus’ call to listen, understand, and live transformed lives. Let us now conclude by reflecting on this life‑changing invitation.”

IV. Conclusion

Closing Illustration: Imagine again my gift to my brother. the beautiful exterior and the disappointing interior.

We don’t want to get to the end of our lives and be just like that.

Reflection: Reflect on the condition of your own heart. Are you truly listening to Jesus’ call, setting aside distractions, and embracing the inner renewal He offers?

Challenge: I challenge you today: turn down the static of conflicting traditions and false voices. Listen deeply to Jesus, allow His transformative work to renew your heart, and disregard the distractions of legalism that do nothing but obscure His truth.

Key Verse: “But those things which come out of the mouth come forth from the heart; and they defile a person.” – Matthew 15:18–19

Commit to regularly setting aside time for focused, prayerful listening to God’s word.

Call to Action:

Dismiss distractions—especially those rooted in outdated traditions or critical voices that pull you away from Christ.

Embrace daily accountability, confession, and fellowship so that the gospel’s transformative power may be evident in every aspect of your life.

Share this invitation to transformation with others, inviting them to hear, understand, and experience the renewing power of Christ’s gospel.

This revised outline highlights Jesus’ clear call for the crowds to “hear and understand” and instructs His disciples—and us—to ignore the distracting emphasis of the Pharisees, keeping our focus on the heart’s renewal through the gospel.

II. The King’s Call to the Disciples: Ignore False Spirituality