The Mortification of Sin

“Be killing sin, or it will be killing you.”

How are believers supposed to deal with remaining sin in their hearts? Those who align themselves with Reformed theology believe in the total or radical depravity of human beings’ hearts. So, even though a believer is free from the dominion of sin (Romans 6) he or she is still under the influence of sin. In order to deal with the influence of sin in the believer the Holy Spirit must put to death or mortify the misdeeds of the body (Romans 8:13).

This putting to death the misdeeds of the body by the Spirit is the subject of John Owen’s masterpiece,The Mortification of Sin. Owen, a Puritan pastor and theologian, lays down this thesis: “The choicest believers, who are assuredly freed from the condemning power of sin, ought yet to make it their business all their days, to mortify the indwelling power of sin. The principal cause of the performance of this duty is the Spirit: ‘if by the Spirit.'” Mortification of sin is putting sin to death at the root level. To “mortify” is “to take away the principle of all [its] strength, vigor, and power, so that [it] cannot act or exert, or put forth any proper actings of [its] own.”

How do we mortify sin? I highlight three points from Owen:

1. Owen makes it plain that only in believers does the Spirit mortify sin. “Mortification is not the present business of unregenerate men.” If a church first calls the unbeliever to mortification and not conversion, the unbeliever will surely be lost. The gospel is the foundation of repentance and mortification. Without the full acceptance of Christ’s atoning finished work on the cross one cannot accept his or her radical depravity. Therefore, anyone trying to mortify sin without first accepting the gospel is on the road to becoming a self-justifier. Owen asks this rhetorical question: “Can sin be killed without an interest in the death of Christ, or mortified without the Spirit?” Owen grieves for those who perform works of righteousness without knowing the righteousness of Christ and the guidance of the Spirit. “There is no death of sin, without the death of Christ.”

2. Get to the root motivation of sin. What is the root of the outward manifestation of sin in a believer? Is it an embedded secret atheism? Is it pride? Selfish ambition? As soon as sin rises, recognize the motivation behind it and put it to death by the Spirit. An unmortified sin is dangerous, even deadly. Sin always wants to go all the way. “Every unclean thought or glance would be adultery, if if could; every covetous desire would be oppression; every thought of unbelief would be atheism, might it grow to its head.” To allow sin to get a foothold in one’s heart is to allow sin to progress to the utmost. Sin is serious and costly.

3. “Set faith at work on Christ.” Once the seriousness and motivation of sin has been discerned one must hold to the promises of Scriptures. This is done by directing one’s faith to the gospel. In the last chapter of the book, Owen writes, “Set faith at work on Christ for the killing of thy sin. His blood is the great sovereign remedy for sin-sick souls. Live in this, and thou wilt die a conqueror. Yea, thou wilt, through the good providence of God, live to see thy lust dead at thy feet.”

If we have understood the motivation and seriousness of our own sin, and then we “set faith at work on Christ” the blood, righteousness, work and cross of Christ will appear to us so sweet, so glorious, so precious, so necessary. The Spirit shows us the love of God through the suffering, death and resurrection of Christ. With God’s love so apparent, sinning is less attractive. Pleasing God becomes more pleasurable than committing sin.

The Mortification of Sin is written from a pastor’s heart with a pastor’s wisdom. This book emerged as a series of sermons Owen delivered, as most Puritan books did. There are no superficial fixes, no simple solutions. Mortifiying sin by the Spirit is necessary. We can’t simply break bad habits. Sin has to have the life taken out of it at the motivational level by the Spirit. We must examine our hearts realistically with the guidance of the Spirit through the mirror of Scripture. Then, the life-changing power of Almighty God works in our hearts.

A note on works: Owen says that “duties are excellent food for a healthy soul; they are no physic (medicine) for a sick soul.” If someone has fallen into grievous sin, works and duties will not help him or her. Owen, in chapter 3, describes a scenario he must have witnessed several times as a minister: “Men are galled with the guilt of a sin that hath prevailed over them; they instantly promise to themselves and God that they will do so no more; they watch over themselves and pray for a season, until this heat waxes cold and the sense of sin is worn off; and so mortification goes also, and sin returns to its former dominion.” Mortification of sin, then, is a work of the Holy Spirit alone. “He causes us to grow thrive, flourish, and abound in those graces which are contrary, opposite, and destructive to all the fruits of the flesh, and to the quiet or thriving of indwelling sin itself.”

I’ve used The Mortification of Sin in my Bible studies and personal counseling, including counseling myself. The book has opened my eyes to what Scripture has to say about the mortification of sin in a believer. The book also offers keen insight on the doctrine of the Holy Spirit, which Owen has written about extensively in his book, The Holy Spirit. I’d recommend Owen’s book without reservation to any believer–old or young. I especially commend it to those who counsel or who teach the Bible regularly. It’s a treasure of wisdom.