The Internal Engine of Righteousness Text: Psalm 37:30-31
Introduction: The Foundation of the Unshakeable Man
We live in an age of profound instability. Men are like reeds shaken by the wind, tossed to and fro by every new cultural current, every new political panic, every new definition of reality that bubbles up from the pit. They seek stability in their portfolios, in their political tribe, in their therapeutic affirmations, but they find none. Their feet are planted on shifting sand, and when the rains descend, and the floods come, and the winds blow, their house comes down with a great crash. And the reason for this is that they have mistaken the outside for the inside. They believe that if they can just arrange the externals correctly, they can manufacture internal peace. They are wrong.
Psalm 37 as a whole is a bracing corrective for the righteous man who is tempted to envy the wicked. The wicked seem to prosper. They are loud, they are flashy, they have the microphone, and their path looks for all the world like a parade. But the Psalmist, speaking as an old man who has seen the whole movie and not just the trailer, tells us not to fret. Their prosperity is a mirage, their path leads off a cliff, and they will soon be cut down like the grass.
In the middle of this exhortation, our text provides us with a portrait of the righteous man. But it is not a portrait of what he does so much as a diagram of how he is constructed. It shows us the internal mechanics of a stable life. The world tells you to project confidence, to speak your truth, to hustle and grind. God tells you that a stable life and an influential voice are not things you manufacture on the outside. They are the inevitable fruit of a profound internal reality. What we see in these two verses is the divine logic of a life that does not slip. It is a life where the law of God has moved from being an external code to being the internal operating system of the heart.
The Text
The mouth of the righteous utters wisdom,
And his tongue speaks justice.
The law of his God is in his heart;
His steps do not slip.
(Psalm 37:30-31 LSB)
The Fruit: Wise and Just Speech (v. 30)
We begin with the observable output, the fruit that is visible to all.
"The mouth of the righteous utters wisdom, And his tongue speaks justice." (Psalm 37:30)
The first thing to notice is that righteousness is not a silent, private affair. It speaks. A man is righteous, and therefore his mouth opens and something of substance comes out. And what is that substance? It is wisdom and justice. These are not two different things, but two facets of the same thing. Wisdom is seeing the world as it truly is, in accordance with the grain of the universe that God established at creation. And justice is applying that true sight to the affairs of men. Justice is rendering to each man his due according to God's fixed standards.
This is not the world's wisdom, which is earthly, sensual, and demonic. The world's wisdom is a mixture of cynical pragmatism and sentimental foolishness. It calls evil good and good evil. It is the kind of "wisdom" that says a man can become a woman, that debt is prosperity, and that killing babies is a healthcare choice. That is not wisdom; it is a sophisticated form of insanity.
The wisdom the righteous man utters is from above. It is rooted in the fear of the Lord, which is the beginning of wisdom. It is the ability to look at a complex situation and see the underlying moral architecture. And because he sees truly, he speaks justly. His tongue does not flatter, it does not equivocate, it does not bend the truth to curry favor. It speaks justice. It calls a thing what it is. This kind of speech is architectural. It builds things. It restores order. It brings clarity where there was confusion. The speech of the wicked, by contrast, is deconstruction. It tears down, it muddies the waters, it creates chaos, because the wicked man is at war with reality itself.
So the righteous man speaks, and his speech has weight. It has this quality because it is tethered to reality. But where does he get this wisdom? How does he know what justice is? The world thinks this comes from a better education, or from being on the "right side of history." The Bible tells us it comes from a different source entirely, a source deep within.
The Root: The Indwelling Law (v. 31)
Verse 31 gives us the reason for verse 30. It shows us the engine that drives the entire enterprise. The righteous man speaks wisdom because of what is happening inside him.
"The law of his God is in his heart; His steps do not slip." (Psalm 37:31 LSB)
Here is the absolute center. "The law of his God is in his heart." As Spurgeon said, this is the best thing, in the best place, with the best results. The law of God is not, for this man, a list of rules in a book on a shelf. It is not an external imposition that he grudgingly obeys out of fear of punishment. It has been internalized. It is written on the very muscle of his heart. This is nothing less than the promise of the New Covenant, prophesied by Jeremiah: "I will put My law within them, and on their heart I will write it" (Jer. 31:33).
When the law is in the heart, it is no longer just a restraint on behavior; it becomes the very source of your desires. You begin to love what God loves and hate what God hates. You don't just avoid adultery; you delight in faithfulness. You don't just refrain from theft; you delight in generosity. The law ceases to be a burden and becomes your native language. It is the grammar of your new nature.
This is the fundamental difference between the righteous man and the Pharisee. The Pharisee's righteousness is all on the outside. It is a performance. He tithes his mint and cumin, but his heart is full of dead men's bones. The righteous man's righteousness is an inside-out reality. Because God's law is in his heart, God's wisdom is in his mouth. Jesus Himself said that out of the abundance of the heart, the mouth speaks. If the heart is filled with the glorious, holy, just, and good law of God, then wisdom and justice will pour out naturally.
And what is the result of this internal alignment with God's reality? "His steps do not slip." This is the great promise of stability. The man whose heart is governed by God's law is a man with good footing in a slippery world. He is not easily knocked over by temptation, by tragedy, or by the taunts of the wicked. Why? Because his foundation is not in his circumstances. It is not in public opinion. It is in the unchanging character of God, reflected in the law that now resides within him.
The wicked, in contrast, are on slippery ground (Psalm 73:18). Their lives are a series of frantic adjustments to their own lusts and the world's lies. They have no internal gyroscope, no true north. And so they inevitably slip and fall into ruin. But the righteous man walks on a level path. His way is established by the Lord because the Lord's own law is his guide from the inside out.
The Gospel Connection
Now, we must be very careful here. It would be easy to read this and think that the path to a stable life is to simply try harder, to grit our teeth and force God's law into our own hearts by sheer willpower. But that is the very definition of self-righteousness, which is no righteousness at all. It is to attempt to establish our own righteousness, and not submit to the righteousness of God (Rom. 10:3).
Who is this righteous man? Ultimately, there is only one man who fits this description perfectly, and that is the Lord Jesus Christ. He is the only one whose heart was ever in perfect, unbroken communion with the law of His Father. He spoke wisdom and justice because He is the Wisdom of God and the Justice of God.
And the good news of the gospel is that through faith, His righteousness is imputed to us. We are declared righteous for His sake. But it doesn't stop there. Justification is not the end of the story. God then begins the work of making us practically what He has declared us to be legally. And how does He do this? He sends His Spirit to dwell in us, and the Spirit begins to do this very work, writing the law of God on our hearts.
The Christian life is the process of that law being inscribed more and more deeply. It is the Spirit conforming our desires, our thoughts, and our words to the pattern of Christ. So the stability described here is not something we achieve, but something we receive as a gift of grace. Our steps do not slip because we are held fast by Christ. Our mouths speak wisdom because we are being taught by His Spirit.
Therefore, the application is not to "try harder to get the law in your heart." The application is to repent of your self-righteousness, to despair of your own ability to generate wisdom or justice, and to flee to Christ. It is to ask God, for Christ's sake, to send His Spirit to do this supernatural work in you. It is to steep your mind in the Scriptures, where we find this law, and to pray that the Spirit would take it from the page and graft it onto your heart. When He does, you will find that your words begin to carry an unfamiliar weight, and your feet begin to find a newfound stability. You will become a source of order and justice in a world that is slipping into chaos, not because of your own strength, but because the law of your God is in your heart.