Fuel for the Furnace

How Your Mind Serves Your Heart

The Gospel Coalition New England 2012 Conference | Boston


What an amazing thing that God would raise up in our generation a voice like Tim Keller’s. I sat there reveling in those four points, and I want to say them again and show you how they launch this message.

The gospel is news, not advice, of something that’s been done for you — outside of you — to which you gladly respond by receiving and believing and enjoying. In fact, if you were to press on me to say what was done outside of you, I would say that Christ bought a gift for you and the gift he bought for you was Christ for your everlasting enjoyment, which was his fourth point. But number two was the gospel does shape a life better than the law because the gospel not only brings direction, it also brings motivation, which was also given in the fourth point.

Third, there were illustrations of the gospel-shaped life finding its amazing “Kelleresque” statement between moralism and relativism — so wise, so necessary. I just hope New England will be filled with that kind of shrewd insight into the essence of the gospel. And then he ended a point that with his briefest, which will be my two messages. This is perfect. Thank you for letting me have your fourth point.

He said, by quoting a Thomas Chalmers sermon, “The Expulsive Power of a New Affection”, which is all I have to say in my Christian Hedonism, and he summed it up by saying, “How does the gospel change or shape our life?” And he said, “By worship.” Implicit in that very shorthand statement is that the new affection that is pushing out sin and ungodliness and idolatry is an affection for God, which he called worship — to which I say, “Amen.”

White-Hot Affection for God

The main point of my two messages is God created you with a mind and with a heart so that the heart, when rightly served by the mind would treasure God with white-hot affection. Only I’m arguing now that the ultimate goal of God in giving you a heart and a mind is found in the act of the heart, not the act of the mind, and that the mind exists to serve that act and when the mind rightly serves the heart, the heart explodes with a new affection, which is profoundly transforming in its affection that is Godward — it’s white-hot for God.

“The gospel is news — not advice — of something that’s been done for you.”

The subordinate point is that because of sin, neither the heart, nor the mind, does what it is supposed to do, but the mind doesn’t serve the heart rightly and the heart doesn’t treasure God with white-hot affection until the gospel saves and shapes the mind and the heart. Implicit in those two points is that the purpose of God in creating you reaches its ultimate end in your heart. Namely, in the treasuring in your heart of God — the treasuring of God above all things with white-hot affection and the mind is given to serve that act through the right apprehensions of reality.

Logic for the Sake of Love

If you apprehended reality for what it really is, your heart would be ignited with a white-hot affection for the supreme reality: God himself. Or to put it several other ways, right thinking about God exists for the sake of right feelings for God — in that order. Logic exists for the sake of love. Reasoning exists for the sake of rejoicing. Doctrine exists for the sake of delight. Reflection about God exists for affection for God. The head is meant to serve the heart. Knowing the truth is the basis of admiring the truth.

Both thinking and feeling are essential. They are not coordinate. Rather, thinking serves affection. The devil has many factually true thoughts, and none of them rightly serve his heart and bring him to love the truth. Therefore, his right thinking is no good. I don’t care how right it is or how factual it is. It aborts. It fails. It doesn’t reach the ultimate goal of people created in God’s image: that the heart would explode with white-hot affection for him. That’s why we’re made. The mind, when it’s rightly serving the heart, brings that forward.

Mind and Heart Work Together

As I say that, I’m aware that Ephesians 4:18 seems to say the opposite. “They are darkened in their understanding, alienated from the life of God because of the ignorance that is in them due to their hardness of heart.” Here, instead of the mind serving the heart well or poorly, the heart is darkening the mind due to its hardness. I’m aware of that. I didn’t craft this thesis statement without awareness of that, which seems to say that if your heart gets right, your mind will get right, which is right. They’re not opposites. My point and this point are not opposites.

There is a reciprocal back and forth relationship between the function of the mind thinking and the function of the heart feeling for God. There’s a reciprocal relationship. What I’m arguing is not that its faults, that if the heart ceases to be hard and becomes supple and tender and alive to the sweet value of Jesus, it won’t liberate the mind from having to constantly defend deceptive affections. It does liberate the mind from having to constantly work out and manipulate and defend defective affections. That’s what the mind of the flesh is. It’s constantly defending against defective emotions, and the mind is thus contaminated by the heart.

“Because of sin, neither the heart nor the mind does what it is supposed to do”

I’m admitting that and saying, “Yes, when we’re born again by the spirit of God, the heart is replaced from a heart of stone to a heart of flesh, which is alive to the infinite value of Jesus, and the mind is wonderfully liberated from all of its deceptions.” And then I ask, “For what? Have we reached the goal then, that the mind has now become the pinnacle so that right thinking about God is what you were made for?” And the thesis of this talk is: no. In the reciprocal relationship, the mind is set free in order that it might continually throw the kindling and the fuel of truth into the furnace of the heart for the flame of love to God. That’s why the mind exists, to serve the white-hot affection of the furnace of your heart for God.

My point is when it’s freed by the transformation of the heart from hardness to tender sensitivities, it then reciprocally goes about its wonderful work of throwing logs of combustible truth into the furnace of the heart for the sake of inflaming love, affection for God.

From Your Whole Heart

Let me give you a text that really points strongly for me in this direction. It’s a little bit technical, but I’ll do it anyway. Luke’s version of the first commandment, spoken by the lawyer, followed by Jesus saying, “You are correct.” Here’s what he said differently from the other Synoptics, I think, in order to draw out my point. Actually, I learned my point from him. It goes like this: “You shall love the Lord your God ex holēs kardias sou — from your whole heart. And en holē tē psuchē — with your whole soul. And en holē tē ischui sou — with your whole strength. And *en holē te dianoia sou — with your whole mind.”

The point is there’s one preposition for heart and three of the same prepositions for strength, soul, and mind. Let me paraphrase it like this: “You shall love the Lord your God from your heart with the aid and assistance of strength and mind and soul, serving the heart from which worship of love explodes to God.” I think that’s what Luke wants us to understand, by making the preposition different for heart. If you would ask me what it means to love God with all my mind, I would not say, “Think right thoughts about God.” So many people say that. I wouldn’t say that. I would say, “Use your mind to stoke your heart with passion for God.” And there is a way to use your mind to stoke your heart with passion for God, and there’s a way to waste it.

Three Ways the Gospel Shapes Your Mind

My thesis remains: God’s purpose for your reaches its ultimate climax not in right thinking about him, but in right affections for him and the right thinking about him is a right serving of the heart, which then is the organ of affection for him. Your mind and your heart can only do that, your mind can only function in a right service to your heart, if it is saved by the gospel and shaped by the gospel. So, I’m going to give you three ways your mind is shaped by the gospel and give you some illustrations from the Bible of how crucial this function of the mind serving the heart is.

1. Insufficient in Itself

The first way that your mind is shaped by the gospel is: since the gospel involves the objectivity of a God outside of you and since it involves the historicity of a Christ outside of you in history and since it involves visible, tangible events — like crucifixion and resurrection — and since it involves articulation with sentences that are construable and hearable, like “he died for our sins,” therefore, the gospel demands that the mind not be a creative organ bringing reality out of itself, but that it submit to the objective, historical, visible, hearable, construable realities totally outside itself. That’s what your mind is for. This is a passionate plea for you to be objective, not subjective, in your submission to truth.

This is very counter-cultural anywhere on the planet today, and I would guess here, as well. That’s the first way the gospel shapes your mind. By the very nature of the gospel, having an objective God and a historical Christ and a visible, touchable, crucifixion and a visible, touchable resurrection, it demands mind deal with that. Don’t just go inside and create your own reality.

2. Freedom for the Captive Mind

Second, the gospel shapes the mind by liberating the mind from self-deceiving, reality distorting bondage to self-exaltation and self-preservation. In Christ, all the destructive powers of my badness are over. I can’t be destroyed by my badness if I’m holding fast to Jesus. The gospel provides an absolutely certain outcome of my final glory. My badness can’t destroy me. My emerging identity as a new person is guaranteed to be supremely glorious someday so that if you saw me in the age to come, you’d be tempted to worship me, just like C.S. Lewis said. Since that’s what the gospel does for us, the mind is wonderfully liberated from having to constantly suppress my badness and create alternative futures for me that make me look good. It’s just Bible. It’s just wonderful.

The gospel shapes my mind by delivering my mind from all of its need to run away from self-incriminating truth, and a lot of truth is John-Piper-incriminating. And if I don’t have a way to solve that, other than suppression, my mind is very skilled at defending me, falsely, and that’s not the right use of the mind, and, therefore, it’s a glorious liberty that comes for the mind with the gospel.

3. Regenerated and Renewed

Here’s the third way that the gospel shapes the mind: the Holy Spirit takes the objective statement of the gospel and makes that gospel mysteriously the instrument of the miracle of regeneration. First Peter 1:23: “You have been born again through the living and abiding word of God, which is the gospel which we preach to you.” Here’s this objective, propositionally stated gospel about events in history and a God and a Christ and a transaction on the cross, and it is articulated with the mind and with the mouth and the Holy Spirit takes it and creates a new being with it.

“Logic exists for the sake of love. Reasoning exists for the sake of rejoicing. Doctrine exists for the sake of delight.”

Here’s the point about how that shapes the mind. The mind is engaged as the organ that perceives, construes, and articulates that gospel, which then serves regeneration, which is the coming alive of a person who is in love with Jesus and doesn’t regard him as boring or mythological anymore. Now, this third point is my first point way back at the beginning. The mind, grasping, articulating, speaking the gospel, is becoming the instrument by which the heart is set on fire through regeneration for an affection for God.

Let’s summarize these three ways that the gospel shapes the mind.

  1. The gospel makes the mind serve objective reality by being objective reality.
  2. The gospel shapes the mind by making the mind serve truth — even when it’s self-incriminating — by freeing me from the need to defend myself since I have an advocate now that can’t be improved upon.
  3. The gospel shapes my mind by forcing it to serve my heart through being the organ of articulating the gospel that the Holy Spirit uses to wake me up to the beauty of God.

Seven Examples of the Mind Serving the Heart

What I want to do with the rest of the time is give you illustrations from the New Testament of how crucial the mind is in serving the heart — or to use Tim Keller’s fourth point: serving the new affection or serving worship. And I would simply say that this is serving the white-hot affection for God that you were made to have in your heart.

1. Zeal According to Knowledge

Romans 10:1–2: “Brothers, my heart’s desire and prayer to God for them [his Jewish kinsmen] is that they may be saved. I bear them witness that they have a zeal for God, but not according to knowledge.”

Here are some hearts of Jewish kinsmen that are passionate for God, and they are hell-bound, lost, perishing sinners. We know that because of verse 1: “Brothers, my heart’s desire and prayer to God for them is that they may be saved because they have a zeal for God,” but not according to minds that are rightly construing reality. They aren’t getting it. Being ignorant of the righteousness of God, they are seeking to establish their own, and they are lost regardless of what passion for God they have.

The point here is if the mind does not serve the heart rightly, the heart can have white-hot affections that are hellish for God. Is that incredible? Tell the Muslims about it, Jews, Hindus, Buddhists. This is a very religious planet. It always will be. That’s number one: Let your mind serve your zeal by bringing truth concerning the gospel into the furnace of that zeal so that when you have it, it does accord with knowledge rather than according with pride.

2. The Lord Gives Through Thinking

Second Timothy 2:7: “Think over what I say, Timothy, for the Lord will give you understanding in everything.” This is a command from Paul to all of you and me. “Think over what I say.” Why? “For the Lord will give you understanding.” That’s remarkable because how many people you’ve met perhaps who say, “Thinking. That’s what counts, and by thinking, you find truth.” That text says, “By thinking, he gives truth.” Others say, “He gives truth. Phooey on all that thinking stuff. It just deadens the heart.” Have you heard that before?

There’s just a huge cleavage in a lot of churches and a lot of people’s lives — the thinkers and the feelers — and I’ve tried to spend most of my life pleading with people not to make that choice because it says, “Think over what I say for the Lord himself in supernatural ways works inside you through thinking.” Don’t limit yourself to thinking that thinking is the key. It’s a path, and the key is in heaven, and he can shut your mind while you’re thinking or open your mind while you’re thinking. The Lord gives, but he doesn’t give apart from thinking.

If you do “yoga” — I think it’s a real sad thing and this is going to offend some of you. You go to those classes, and you think there’s no religious dimension to that cross-legged, empty-headed thing. There is a religious dimension to it. Emptying the head is not the way the Lord gives. It’s not. The Lord gives to thinkers who open their Bible and say, “O, God, what does this mean? Help me to see what these words mean. I will study with all my might, but I must have you.” That’s number two.

3. The Heart Opens Through the Mind

Acts 17:2–3: “Paul went into the synagogue as was his custom, and on the three Sabbath days, he reasoned with them while from the Scriptures explaining and proving that it was necessary for the Christ to suffer and rise from the dead.” Paul is reasoning, explaining, and proving. He’s engaging the organ of his mind and addressing people with rational content, and he knows because he’s the one who taught us that these people I’m talking to are dead in trespasses and sins. They’re dead. He knows that the mind of the flesh does not receive the things of the spirit. He knows that the god of this age is blinding the minds of unbelievers to keep them from seeing the light and the beauty of what he’s saying. He knows all that, and he keeps on talking with rational arguments and sentences from the Old Testament, trying to reasonably persuade them that the Christ must really suffer and rise from the dead. Why? Because God has ordained that the mind serve the heart. That’s what he has ordained.

When Paul, in the previous chapter approached Lydia, who got saved, do you remember what it said about her conversion? This is a very important sentence in the Bible Acts 16:14: “The Lord opened her heart to give heed to what was spoken by Paul.” It’s not, “She’s dead, she’s got the mind of the flesh, the god of this world is blinding her, there is no point in talking to her, zombies don’t hear.” Oh, yes, they do. Lazarus heard. The gospel is the power of God unto salvation. The gospel looks out on dead people and says, “Live. In the name of Jesus Christ, rise and walk.” The words, the rational words and the arguments are used by the sovereign Holy Spirit to open hearts, to give heed to that. The very words become the means by which the dead live.

My point is the mind, in construing the meaning of history and the cross and the gospel, and then the mind in articulating it in sentences that can be grasped by human brains becomes the instrument by which the Holy Spirit and his supernatural power opens the heart, raises the dead, gives eyes to the blind, gives an ear, and saves sinners so that they have a white-hot affection for Jesus.

“My badness can’t destroy me. The gospel provides an absolutely certain outcome of my final glory.”

4. Simple Logic

Jesus assumes that we will use logic. This is an argument. Here’s the background for this in my life. I remember going to school in the days when Hebraic thought and Hellenistic thought were opposites — big conflict. And it was avant-garde to say, “Hellenistic bad. Hebraic good. Platonic Aristotelian foreign. This indigenous to the Bible.” I would listen to this stuff and I’d say, “I don’t think so. That doesn’t make sense to me.” I didn’t know anything about Hellenistic thought, so how could I judge? Well, I just grew up in a Bible-thumping home. My mom and then my dad just read me Bible over and over again, and I just smelled that stuff. Then later on, I began to be able to explain things, so listen to this and see if you think this is right.

Luke 12:54–57, “He said to the crowds, ‘When you see a cloud rising in the west, you say at once, ‘A shower’s coming.’ And so it happens. And when you see the south wind blow, you say, ‘There will be scorching heat,’ and it happens. You hypocrites! You know how to interpret the appearance of the sky and the earth. Why don’t you know how to interpret the present time?”

What’s that mean? He’s saying, “You use Aristotelian logic every day of your life, and you won’t bring it to bear on the things that really matter.” Aristotelian logic is built on a syllogism.

All men are mortal.
Plato’s a man.
Therefore, Plato’s mortal.

Is that Western? Foreign to the Bible? It’s right there. You get up in the morning, red sky — premise number one. Premise number two: red sky means it’s going to be dangerous today, going to be a bad, windy day. Conclusion: it’s going to be a bad, windy day because it happens every day when it’s red. This is not Western. This is human. This is God. This is the brain of God.

He got really bent out of shape at these people. You hypocrites, drawing down inferences with such clear logic that you know how to go out on the Sea of Galilee when it’s safe and not to go out when it’s safe because when it’s red, you got premise one, and you know premise two is all red days are dangerous days, and so this must be a dangerous day, so I’m not going out. And you won’t do that with your brain for the gospel truths all around you.

I don’t like it when people dump on thinking as though it were somehow foreign to Christ and to his word in clear, old Aristotelian, syllogistic ways.

5. Renounce Underhanded Ways

Here’s another one that really got Jesus bent out of shape. Matthew 21:23 following. You look for how the mind is used in this story. This is so relevant for our day. “When he entered the temple, the chief priest and the elders of the people came up to him as he was teaching and said, ‘By what authority do you do these things and who gave you this authority?’ Jesus answered them, ‘I’ll ask you a question, and if you tell me the answer, I’ll tell you by what authority.’”

What’s Jesus doing? He’s giving them a test to see whether they’re the kind of people he’s willing to talk to. This is really important. Do you want to be the kind of person whom Jesus is willing to answer? I do. This is the text that will tell me one of the ways I can be that kind of person:

Jesus answered them, “I also will ask you one question, and if you tell me the answer, then I also will tell you by what authority I do these things. The baptism of John, from where did it come? From heaven or from man?” And they discussed it among themselves, saying, “If we say, ‘From heaven,’ he will say to us, ‘Why then did you not believe him?’ But if we say, ‘From man,’ we are afraid of the crowd, for they all hold that John was a prophet.”

What are they doing? They’re using their brains. They’re sharp guys. They’re using their brains, and they’re saying, “If we say this, then he’ll trap us by saying, ‘You didn’t believe on him,’ and we don’t want to be trapped because our ego will be hurt.” The other alternative was getting stoned because the people think he’s a prophet. So if they say, “It’s just human. They’re going to get really mad at us. We love our flesh and we love our ego, so what are we going to use our brains to do?” This is total politics. We will say, “We don’t know.”

“So they answered Jesus, ‘We don’t know.’ And Jesus said, ‘I won’t tell you by what authority I do these things. I won’t talk to you. I hate that use of the brain my Father gave you.’” Spin to protect yourself. Zero interest in the truth. Zero. Just ego. Flesh. This is really important. I just so long for Christians to be different. If you ever run for office, answer the question.

What a witness. What a witness. If you ask, “Is there a biblical statement about the alternative to that, that ugly manipulation of truth to escape your ego issues and your danger issues? Is there an alternative,” I’ll read you a beautiful alternative. I love the apostle Paul. Cost him his life to be this kind of man, but let me read it to you. Second Corinthians 4:2: “We have renounced disgraceful and underhanded ways. We refuse to practice cunning or to tamper with God’s word, but by an open statement of the truth, we would commend ourselves to everyone’s conscience in the sight of God.”

“If you want to alienate Jesus, start being cunning and underhanded with your brain.”

O, Lord, make it happen in New England. May this room be filled with people like that, renouncing all disgraceful, underhanded, cunning ways. Oh, the brain can be misused. Oh, the brain, the brilliant, beautiful gift of God to serve the heart’s passion for Jesus can be turned into cunning. He would not talk to them, and if you want to alienate Jesus, start being cunning and underhanded with your brain.

6. Do You Not Know?

In Paul’s letters, there are thirteen times where he asks the question, “Do you not know?” Remember that question? “Do you not know?” What’s he saying when he asks that? “Do you not know?” “Do you not know?”

  • 1 Corinthians 3:16: “Do you not know your body is the temple of the Holy Spirit?”
  • 1 Corinthians 6:3: “Do you not know we will judge angels?”
  • 1 Corinthians 5:6: “Do you not know a little leaven leavens the whole lump?”
  • 1 Corinthians 6:9: “Do you not know unrighteousness will not inherit the kingdom of God?”
  • 1 Corinthians 6:15: “Do you not know your bodies are members of Christ?”
  • 1 Corinthians 6:16: “Do you not know that he who is joined to a prostitute becomes one body with her?”

What’s he doing? The point is that if you knew, you’d know how to act. If you knew, you’d know how to think. If you knew, it would make a difference in your life, and you’re acting as though you didn’t know that you’re going to judge angels when you can’t even fix a little problem of a dispute in the church and you go get a pagan judge to work on it because you know something. The knowing of something is going to keep you from doing that. You’re going to judge angels. Isn’t that amazing? This is amazing to me that Paul would use knowledge with such force to say, “It really does change the way you behave, the way you feel, the way you live.” It does because it changes your heart. Thinking rightly and knowing the truth are crucial to valuing the truth and living the truth.

7. Read to Perceieve

And here’s my last one. It’s so obvious, so simple, and yet so amazingly profound. The Bible is a book. There it is. It’s a book. We call it the word of God. It exists objectively, outside of me, containing truth. Jesus Christ came into the world as the truth. We love that. We learn it here, but when he was finished with his work and returned, he left behind apostles — prophets who became the foundation of the church — and what they did in founding the church was right, inspired guidance and teaching for the church, which became enshrined in the second half of our Bible called the New Testament. Now we have the word of God in a book. God did not have to do it this way. Could have done it with videos. Could have done it with the Internet. He could have caused the incarnation to happen in our century. He chose to preserve his holy, inspired, inherent word in a book.

The implications of that historically are simply mind-boggling in terms of how Christian mission is done and what happens when the church takes root in a preliterate culture. Everything changes. Everything changes over time. It might take centuries, but it changes. This changes everything. That is, a book changes everything. That it must be read to have any influence at all and to read is to be educated, and to be educated is to learn to think and to read well is to think well, and here’s a verse to show you the connection between what it says and what it is.

I remember teaching Ephesians about 35 years ago and seeing this for the first time. In Ephesians 3:4 Paul says, “When you read this [his letter] you are able to perceive my insight into the mystery of Christ.” Do you wonder why Christians found schools? Raised their kids up by teaching them to read early? “When you read this, you will be able to perceive my insight into the mystery of Christ.” Because the Holy Spirit who inspired the book is jealous to use the book to open our eyes to see the glories of what’s in the book, but not without reading. That is thinking. That is the use of the mind to throw kindling into the furnace of the heart for the flame of affection. Not without thinking.

“Spare no effort to think rightly so that you will be pouring fuel into the furnace of the heart.”

Fuel for the Furnace

Here’s a summary of what I’ve tried to do. God created you with a mind and with a heart, an organ of thinking and reflection, pondering, meditating, truth-handling, and a heart, an organ of affection and emotion and feeling, inclination, and the mind, when it’s rightly serving the heart causes the heart to be aflame with Christ as a supreme treasure.

Brothers and sisters, spare no effort to use your mind. Spare no effort to think rightly so that you will then, by your mental apprehension of truth — wherever it comes from, especially in the word, by your mind, the right use of it — you will be pouring fuel into the furnace of the heart for the sake of inflaming a white-hot affection for God.


Read, watch, or listen to the companion message: