I am currently working through the Richard Rushing abridgement and modernization of John Owen's The Mortification of Sin and am finding it so helpful that I've decided to post some brief excerpts and part of the outline of the book over the next few days. This will only be a sketchy and unpolished assortment of thoughts, but will give you a flavor of Owen's profound depth of insight into the nature of sanctification.
First, a definition. If you don't know already, "mortification" refers to the killing of sin. Owen's most famous lines may be "be killing sin or it will be killing you." But as his book reveals, there is much more to the true killing of sin than merely opposing sinful behavior in our own lives. Mortification is a spiritual work that can only be accomplished through spiritual means used by spiritually renewed people.
Owen's meditations are primarily based on Romans 8:12: "If by the Spirit you put to death the deeds of the body, you will live." The introduction to the book shows the following five things.
1. The exhortation is directed to believers. See Romans 8:1-11 for context. These are people in whom the Spirit of Christ resides, who are in Christ, and for whom there is now no condemnation. Owen says, "The choicest believers, who are assuredly freed from the condemning power of sin, should also make it there business all of their days to mortify the indwelling power of sin." (p. 2). That is just another way of saying that those who are justified must also be sanctified. Or that when God cancels the guilt of sin, he also breaks the power of sin in our lives.
2. The condition expresses the clarity of the relationship. "IF by the Spirit you put to death the deeds of the body, you will live." Implication: if you do not, you will not live, but die. This is not because mortification (putting to death the deeds of the body) is the cause while eternal life is the result, but that mortification is the means and eternal life the end. God's grace in Christ is the cause. But God works through means.
3. Our strength in the performance of this duty comes through the Spirit. "All other ways of mortification are in vain," says Owen. In fact, in one of the most important statements of the book, Owen writes that "mortification from a self-strength, carried on by ways of self-invention, to the end of a self-righteousness, is the soul and substance of all false religion in the world" (p. 3). Mortification is not moralism or self-reformation. It is the work of the Spirit in the life a believer - a work of grace grounded in the gospel of the death and resurrection of Christ. It is not about turning over a new leaf. but about becoming a new person.
4. Then Owen explains the duty itself by defining three things. (i) The body - which is the flesh. "We are not debtors to the flesh, to live after the flesh; 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." The body is "indwelling sin, the corrupted flesh or lust" (p. 3). (ii) The deeds of the body, which Owen takes to be not only the outward expressions of sin, but also the inward lust. (iii) Mortify - "To 'mortify' means to put any living thing to death . . . to take away the principle of all its strength, vigour, and power, so that it cannot act, or exert, or put forth any proper actings of its own" (p. 3). "It is the constant duty of believers to render a death blow to the deeds of the flesh, that they may not have life and strength to bring forth their destructive influence" (p. 4).
5. The promise of life. "If you live after the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live." This means both "eternal life in heaven, but also the spiritual life in Christ which we have here" (p. 4). "The vigour, power, and comfort of our spiritual life depend on the mortification of the deeds of the body" (p. 4).