There are two famous verses in the New Testament that use the same Greek word, and on the surface they appear to be saying opposite things.
“the Word became flesh” (John 1:14, NET)
“I know that nothing good lives in me, that is, in my flesh” (Romans 7:18, NET)
The word is sarx. John uses it about Christ. Paul uses it about himself. In John, the sarx is what the eternal Word willingly took on, in an act of love that orthodox Christology calls the incarnation. In Paul, the sarx is the part of himself he cannot trust — the resident of his own being that keeps producing what he does not want.
Same word. Different work. And the whole of Christian anthropology — what we are, what we became in Adam, what Christ took on, what is being saved, what is still being fought against — runs through how those two uses fit together.
The Word
σάρξ (sarx), pronounced SARX. One syllable. A feminine noun, third declension. The family includes the adjectives sarkikos (fleshly, of-the-flesh, characteristic of flesh) and sarkinos (made of flesh, fleshly in substance). Our English word sarcophagus descends from sarx — literally “flesh-eater,” a stone box that consumes the body inside it.
At its lexical baseline, sarx means the soft tissue of a living body — meat, in the most ordinary sense. Greek butchers used the word. So did Greek physicians. So did the Septuagint translators, when they needed a word for the Hebrew basar, which carries a similar range from literal flesh to mortal humanity to the human kindred you share blood with.
The New Testament inherits the range and extends it. Sarx in the New Testament can mean any of several things — flesh as physical tissue, flesh as mortal embodied humanity, flesh as the human nature in its weakness, flesh as the human nature in its sinful bondage, flesh as ethnic descent, flesh as the realm of human achievement apart from God. Context governs which sense is in play. And in some passages — most of them Paul’s — more than one sense is operating at once.
This is the kind of word where translation philosophy makes a real difference, and we will come to that.
Range of Meaning
In its New Testament usage, sarx covers:
- Literal flesh, the soft tissue of a body. The medical sense.
- The body considered as physical, bounded, mortal. The contrast is often with pneuma (spirit), explored in Pneuma.
- Human nature in its created weakness — limited, dependent, mortal, but not in itself sinful. The sense John uses in John 1:14.
- Human nature in its sin-bondage — the sense Paul typically uses when he contrasts life “in the flesh” with life “in the Spirit.” Not a part of the person; the whole person under the dominion of sin.
- The sphere of human achievement apart from God’s gift — confidence “human credentials” (Phil 3:3–4, NET).
- Ethnic descent or biological family — “my people, my fellow countrymen” (Rom 9:3, NET).
Two of these senses do most of the theological work in the New Testament. The first is the neutral or honorable sense — flesh as the genuine human substance Christ assumed. The second is the negative sense — flesh as the bondage-state of humans apart from the Spirit. The first sense is required for the doctrine of the incarnation. The second sense is required for the doctrine of original sin. They are not in tension. They are looking at the same human reality from different angles.
Where You’ll Meet It
“Now the Word became flesh and took up residence among us. We saw his glory—the glory of the one and only, full of grace and truth, who came from the Father.” (John 1:14, NET)
This verse is also explored in Logos, Monogenes, and Doxa. Here the focus is sarx. The eternal Word became sarx — real human flesh, not the appearance of flesh, not a phantasm, not a disguise. Whatever sense sarx is going to do later in Paul, the sense John reaches for here is the honorable one. The flesh is what God in the Son willingly took to Himself, that He might save it.
“For I know that nothing good lives in me, that is, in my flesh. For I want to do the good, but I cannot do it.” (Romans 7:18, NET)
Paul, speaking the Pauline sense at full volume. The sarx in him is the thing in him that produces what he does not want and cannot manage to produce what he does want. This is not Paul saying his body is bad. It is Paul saying that the totality of his existence considered apart from the gift of the Spirit is in bondage to a power he cannot escape on his own. The flesh is not a part of him. It is him, in his condition apart from rescue.
“For those who live according to the flesh have their outlook shaped by the things of the flesh, but those who live according to the Spirit have their outlook shaped by the things of the Spirit. For the outlook of the flesh is death, but the outlook of the Spirit is life and peace,” (Romans 8:5–6, NET)
The contrast in shorthand. Sarx and pneuma — flesh and Spirit — are not two parts of the Christian. They are two ways of being human. To live “according to the flesh” is to live in the bondage Adam handed down. To live “according to the Spirit” is to live in the freedom Christ has given.
“I have been crucified with Christ, and it is no longer I who live, but Christ lives in me. So the life I now live in the body, I live because of the faithfulness of the Son of God, who loved me and gave himself for me.” (Galatians 2:20, NET)
The verse where both senses sit in the same sentence. The life Paul lives “in the flesh” — the embodied, daily, ordinary life he is still living — he lives by faith. The flesh here is the mortal embodied existence; it is not bad. But the same Paul will say in the Nomos entry that flesh and Spirit are at war within him (Gal 5:17). One word; two senses; both present in adjacent paragraphs. Context tells you which is in play.
“But I say, live by the Spirit and you will not carry out the desires of the flesh. For the flesh has desires that are opposed to the Spirit, and the Spirit has desires that are opposed to the flesh, for these are in opposition to each other, so that you cannot do what you want.” (Galatians 5:16–17, NET)
The classic flesh-versus-Spirit text. Paul is not saying that you have a lower nature and a higher nature, and the trick is to feed the higher and starve the lower. He is saying that the Christian is in the middle of a fight between two ways of being human — the bondage-flesh of the old self and the freed-Spirit of the new self — and that the fight is real, and that the flesh is genuinely opposed to what you most want as a Christian.
What Confessional Lutherans Hear
The confessional tradition hears sarx with two emphases most of the church has let slip.
First, the word does not split into two words in English without losing something. In the NIV (and some other modern translations), Paul’s negative use of sarx is rendered “sinful nature” — “the desires of the sinful nature” rather than “the desires of the flesh.” The translators’ intent was good: they wanted to keep readers from thinking Paul meant that bodies are bad, or that the physical aspect of human life is inherently sinful. That worry is real, and the Greek-philosophy reading of sarx (flesh = lower physical self, opposed to higher spiritual self) is a misreading that needs to be guarded against.
But the cost of “sinful nature” is high. It splits a single Greek word into two English words, and it loses the connection to John 1:14 (“Now the Word became flesh and took up residence among us.”) and to Galatians 2:20 (“So the life I now live in the body, I live because of the faithfulness of the Son of God, who loved me and gave himself for me.”). When the same Greek word does both jobs — naming the genuine human substance Christ took, and naming the sin-bondage from which we are being saved — the same English word should do both jobs too. “Flesh” lets the reader see what Paul is doing. “Sinful nature” makes one of the jobs invisible and turns the other into a kind of compartment.
It also makes a quiet anthropological claim Lutherans do not want to make. “Sinful nature” sounds like a part of you — a sub-personality, a department within the self, the bad-room of the house. Pauline anthropology is sharper. Sin is not a room in the house. Sin is the condition of the whole house. The flesh is not part of you; it is you, considered in your Adamic condition apart from the Spirit’s gift. When Paul says nothing good dwells in his flesh, he is not saying nothing good dwells in his liver. He is saying nothing good comes from the version of him that is not yet under the Spirit’s reign — and that version is the whole of him, considered apart from grace.
Many translations retain “flesh.” This study uses that term when discussing the Greek word itself; the NET’s rendering varies with the context.
Second, the flesh remains in the Christian. Lutherans hold what the tradition calls simul iustus et peccator — simultaneously righteous and sinner. The Christian, in Christ and on account of Christ, is fully righteous before God. The Christian, in the flesh and in the daily life of Adam’s children, still has sarx that is not yet what it will be. Sanctification is real. The Spirit does His work. But the flesh does not go away in this life. The old Adam continues to need drowning. The new self continues to need feeding.
This is one of the places confessional Lutherans differ from some traditions. Methodist and holiness movements have sometimes held that complete sanctification — the eradication of the sarx — is possible in this life. Some Pentecostal teaching has held similar things. We hold that the New Testament does not promise this. What it promises is that the war is real, that the Spirit will win, and that the day is coming when the flesh will be gone. That day is not today. Today the Christian wakes up still in the body of this death, still needing the Spirit, still being remade. And that is fine. That is what the Christian life looks like.
The pastoral payoff: when you find yourself doing what you do not want to do, you have not necessarily lost your salvation, fallen out of grace, or proved yourself a hypocrite. You have encountered the flesh you still have. The remedy is not to despair, and it is not to redouble your effort by sheer willpower. The remedy is daily repentance, daily faith, and the means of grace — Word and Sacrament — that put you back in the company of the Christ who has already won the war the flesh is still fighting in your members.
Where People Get It Wrong
Three common ways.
The first is the Greek-philosophy misreading. In Platonic and later Greek-philosophical thought, the body (soma) and the soul are opposed — the soul is the higher reality, the body is the lower drag on it, salvation is the soul escaping the body at death. Sarx in this misreading becomes the body specifically, and the Christian life becomes a project of taming the body to free the soul. This is not Paul. Pauline anthropology is Hebrew through and through. The body is good; God created it; God will resurrect it. Sarx in the negative sense is not the body; it is the whole human being in bondage to sin. The contrast is not body-versus-soul. It is bondage-versus-freedom.
The second is what we might call NIV-style compartmentalization. By rendering sarx as “sinful nature,” the translation creates the impression that you have a sinful part and (presumably) a non-sinful part, and the Christian life is about strengthening one and weakening the other. Pauline anthropology is more total than this. Sin is not a part of you. Sin is your whole self in bondage. That is why the gospel is not “improve yourself” but “be raised from the dead with Christ” — a categorical change, not a partial one. The translation choice that obscures this also tends to obscure the gospel that addresses it.
The third is perfectionism — the belief that the sarx can be eliminated in this life. This belief has a long and varied history in Protestant Christianity. Confessional Lutherans hold that it does not match the New Testament’s actual picture of the Christian life, which is the picture of an ongoing war between flesh and Spirit, with real progress and real setbacks, until the day Christ returns and the war is finally over. The Christian who expects the war to be finished in this life will be discouraged when it is not. The Christian who expects to fight the war faithfully, with grace daily renewed, will not be surprised by the flesh’s persistence — and will recognize the flesh’s defeats as the foretastes of the final victory they actually are.
So What
The doctrine of the sarx is not optional theology. It shapes how we hear the Bible, how we live as Christians, how we counsel one another, and how we read our own struggles.
When the Word became sarx, He took on what we are — not the appearance of it, not a sample of it, but the substance. The atonement requires this. If Christ did not become sarx, the sarx is not saved. The first sense of the word is the ground of the gospel.
When the Christian lives in the sarx and against the sarx, both at once, this is not a failure of sanctification. This is what Paul promised the Christian life would look like. The flesh remains; the Spirit wars against it; the outcome is sure but not yet seen. This is the second sense of the word, and it is the realism of the Pauline gospel.
For Sunday school teachers and Bible study leaders: when your students hit Romans 7 and panic — wondering whether Paul’s experience of wanting to do good and not being able is a failure of his Christian life, or whether they themselves are failures because they recognize it — your job is to tell them the truth. This is what Paul promised. This is the sarx. This is the Christian life this side of glory. The fact that you recognize Romans 7 in your own experience is not a sign of spiritual failure. It is a sign that you have understood Paul. And the chapter does not end at verse 24’s cry of misery; it ends at verse 25’s “Thanks be to God through Jesus Christ our Lord.”