The Mortification of Sin

What The Mortification of Sin is

The Mortification of Sin in Believers is a short theological treatise — really an expanded set of sermons — by the English Puritan John Owen, first printed in London in 1656. Owen wrote it as a working pastor and an Oxford academic during the Cromwellian Interregnum, addressing the question of how a real Christian fights a real sin that keeps coming back. The book runs fourteen chapters and was published when he was thirty-six; it has never been out of print since.

Structurally it is an exposition of a single verse, Romans 8:13. Owen breaks the verse into clauses and works each one in order — who the agents are ("if you"), what the means is ("by the Spirit"), what the action is ("put to death"), what the object is ("the deeds of the body"), and what the promise is ("you will live"). The result is more spiritual surgery than self-help: Owen is interested in what is actually happening inside a believer who is trying, and often failing, to kill a sin.

Why serious readers across traditions still reach for Owen

Most books on the Christian life either flatten sin into bad habits to be managed or inflate it into an identity to be despaired of. Owen does neither. He treats sin the way a careful physician treats a chronic condition — naming the mechanism, mapping the patterns, refusing both panic and complacency. That clinical seriousness is why the book has been picked up by readers far outside the Puritan world. Reformed pastors quote it constantly. Anglicans recommend it in spiritual direction. Wesleyan and holiness writers have drawn on it for centuries. Even Catholic spiritual writers have cited Owen’s diagnostic rigor with approval, even where they would not share his ecclesiology.

What unites those readers is not agreement with every line of 17th-century Reformed theology. It is the recognition that Owen knows what he is talking about. The book’s authority is not borrowed from a tradition; it is earned, sentence by sentence, by the accuracy of its descriptions. When Owen names the move your conscience makes when it is trying to negotiate with a sin you secretly do not want to give up, the response is usually the same: how did he know.

The Romans 8:13 framework: Owen’s spiritual diagnostics

Owen builds the entire book on the structure of Romans 8:13 — "If by the Spirit you put to death the deeds of the body, you will live." Every clause is treated as a load-bearing piece of an argument. The "if" rules out passive Christianity. The "by the Spirit" rules out white-knuckle moralism. The "put to death" rules out polite management of pet sins. The "deeds of the body" specifies the object — not bodies as such, but the concrete acts and habits sin produces through them. The "you will live" supplies the promise and the stakes. Owen will not let any clause be skipped, and he spends multiple chapters on the mechanism of how the Spirit actually works mortification in a believer rather than around them.

Out of that framework comes the diagnostic core of the book: nine signs that a particular sin has fastened deeper than the reader suspects, and detailed counsel for what to do once a sin has been honestly named. Owen is interested in self-deception more than almost any other writer of his era — he keeps catching the reader in the act of preferring vague conviction to specific repentance. For readers used to devotional writing that addresses sin in the abstract, the experience of being addressed in the particular is the book’s signature jolt.

"Be killing sin or it will be killing you" — the line and the logic behind it

The most quoted sentence in Owen — and arguably in Puritan literature generally — is a single line from chapter two: "Be killing sin or it will be killing you." It gets reprinted on coffee mugs and tattooed on forearms, which is a fate Owen would not have predicted and probably not have endorsed. But the line is doing real work in its original setting. It is the hinge of his argument that there is no neutral state in the Christian life with respect to a known sin. You are either actively putting it to death or it is actively putting your spiritual vitality to death. Drift is not available as a third option.

Read in context, the line is less a motivational slogan than a clinical observation. Owen has just argued that sin is not a static enemy you can quarantine but a living principle that grows when ignored. He compares it to a wound that, left alone, does not heal but festers. The reason the quote has survived four centuries is not that it sounds tough; it is that almost every Christian who has tried to leave a sin alone and hope it would fade has eventually discovered Owen was right. The line lands because the diagnosis lands.

Original vs. modernized: which edition to actually buy

The honest review of any 17th-century Puritan work has to address the prose. Owen writes in long, periodic, Latin-inflected sentences with embedded subordinate clauses and theological vocabulary the average modern reader was never taught. Even literate Christians who read widely often find the first chapter slow going. This is not a flaw in the reader — it is a genuine gap between 1656 English and 2026 English, and pretending otherwise has caused a lot of people to give up on Owen after fifteen pages and conclude the Puritans are not for them.

The good news is that several modernized editions now exist and are quite good. Crossway’s Overcoming Sin and Temptation, edited by Kelly Kapic and Justin Taylor, keeps Owen’s original sentences but supplies footnotes, definitions, and editorial introductions that turn the book into something more like a guided reading. Aaron Renn’s 2024 paperback goes further and rewrites the prose into contemporary English while preserving the argument and structure. The Banner of Truth Puritan Paperback sits in between — lightly modernized spelling, but largely Owen’s own sentences. For most first-time readers, Renn or Crossway is the right starting point; the original Banner edition rewards a second reading once you already know what Owen is doing.

Pricing

Where The Mortification of Sin falls behind

No application to specific sins. Owen is working at the level of mechanism, not example. Readers expecting a chapter on lust, anger, envy, or addiction by name will not find it. The framework is meant to be applied; it is not pre-applied for you.

Almost no pastoral warmth on the front end. Owen does not coax the reader in. He assumes you already know sin is serious and you already want to fight it. Books like Gentle and Lowly do the pastoral warming-up that Owen skips, which is one reason the two pair so well.

Dated cultural frame. The 1656 context shows in occasional references, examples, and assumptions about church life that no longer translate. Modern editions footnote the worst of these, but the book is unmistakably a 17th-century artifact and never pretends otherwise.

No structured workbook component. There are no journaling prompts, no end-of-chapter questions in the original, no exercises. Some study editions add a discussion guide, but Owen himself supplies argument, not application machinery.

Difficulty curve is real. Even in modernized editions the conceptual density is high — Owen layers distinctions on distinctions, and skim-reading produces almost nothing. Readers who want a book they can absorb in airport-gate sittings will struggle.

The Mortification of Sin vs. The Pursuit of God vs. The Imitation of Christ

These three books often sit on the same shelf and get recommended in the same breath, but they are doing very different things. The Mortification of Sin (1656) is a diagnostic — it works the mechanics of fighting a specific known sin and is at its best when the reader has a particular battle in view. The Pursuit of God (1948) by A.W. Tozer is a meditation on the felt knowledge of God — shorter, warmer, more devotional in cadence, aimed at reawakening hunger rather than diagnosing pathology. The Imitation of Christ (c. 1418-1427) by Thomas à Kempis is a daily devotional in the late-medieval monastic tradition — short readings, contemplative tone, centuries of Catholic and Protestant use.

Different strengths. Owen is the surgeon. Tozer is the spiritual director. à Kempis is the daily companion. A reader who picks up Owen expecting Tozer will find him cold; a reader who picks up Tozer expecting Owen will find him thin; a reader who picks up à Kempis expecting either will find a different genre entirely. The honest recommendation is that serious readers eventually own all three and use them for the work each one actually does.

If you are going to read only one of the three, the choice tracks the question you are actually asking. If the question is "how do I kill this particular sin," Owen. If the question is "how do I want God again," Tozer. If the question is "how do I form a daily habit of meditation," à Kempis. None of the three substitutes for the others, and pretending otherwise tends to disappoint readers in all three directions.

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