Owen begins the book by establishing for us the verse that serves as the premise of the study, Romans 8:13, “For if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live.” Rob Edwards suggests reading Romans 8:1-17 “to see the broader context for this particular verse, paying attention to the work of the Spirit as it relates to the work of Christ and to the Christian life.” And I second that suggestion.
After stating the goal of his writing (which includes an emphasis that he would not be expounding upon the first half of the verse), Owen breaks his foundational text into five points that we must consider.
First, he highlights that Paul’s use of the conditional if expresses the certainty of obtaining life should the deeds of the body be killed. Helpfully, he reminds us that the connection between mortification and life “is not of cause and effect properly and strictly, for ‘eternal life is the gift of God through Jesus Christ’ (Rom. 6:23); but of means and end: God hath appointed this means, for the attaining that end which he hath freely promised. Means, though necessary, have a fair subordination to an end of free promise” (21). In other words, life is not technically the effect of mortification’s cause; instead, mortification is a means by which God freely gives life. Thus, this condition is not a burden for all who truly belong to Christ but a marvelous promise! If you kill your sin, you will have life!
How is our duty to mortify sin an expression of God’s grace rather than a legalistic demand?
Second, he points to the surrounding context of Romans 8 to show that you in verse 13 means believers alone. He notes that pressing the task of mortifying sin upon anyone else “is a notable fruit of that superstition and self-righteousness that the world is so full of: the great work and design of devout men ignorant of the gospel (Rom. 10:3, 4; John 15:5)” (21). Killing sin apart from the grace of Christ creates the most wicked of Pharisees.
Why can non-Christians not be expected to mortify their sins?
Why does mortification apart from the gospel lead to “superstition and self-righteousness”?
Third, Owen emphasizes that we can only put to death our sins by the Spirit. “All other ways of mortification are vain; all helps leave us helpless; it must be done by the Spirit” (22). He goes on to add the poignant warning that: “Mortification from a self-strength, carried on by ways of self-invention, unto the end of a self-righteousness, is the soul and substance of all false religion in the world” (22).
In what ways have you attempted to defeat your sin without relying upon the Spirit? What effect did that produce in the end?
Given the context of Romans 8, how does the Spirit enable us to kill our sin?
Fourth, he clarifies the meaning of the phrase mortify the deeds of the body by explaining “(i) What is meant by ‘the body’; (ii) What by ‘the deeds of the body’; (iii) What by ‘mortifying’ them” (22). He proceeds to explain that the body (or the flesh) “is the indwelling sin, the corrupted flesh or lust” (22-23) that still dwells within us. The deeds of the flesh are “the outward actions” (23) of our internal corruption. Finally, to mortify simply means to kill or to put to death. “To kill a man, or any other living thing, is to take away the principle of all his strength, vigour and power, so that he cannot act, or exert, or put forth any proper acting of his own” (23-24), which is what we must strive to do to our indwelling sin.
Why does Paul in Romans 8:13 call our indwelling sin ‘the flesh’ or ‘the body’?
Why is it important to understand that outward sin is only the manifestation of our inward corruption?
Why is killing a fitting metaphor for how we are to attack our sin?
Fifth, the promised end of mortifying sin is life. Owen notes “the word may not only intend eternal life, but also the spiritual life in Christ which here we have; not as to the essence and being of it, which is already enjoyed by believers; but as to the joy, comfort and vigour of it” (24). In other words, this promise of life is not only the eternal life that is to come but spiritually healthy and joyful life here and now.
What are the two meanings of life that Owen highlights, and why are they both essential for motivating us to kill our sin?
 Rob Edwards, Study Guide for John Owen’s The Mortification of Sin, 6.