Here in chapter 2, Owen addresses the first of three main principles made about our call to mortify our sin (the next two principles are the subjects of chapters 3 and 4). This first principle is that even the very best believers must still mortify “the indwelling power of sin” each and every day of their lives (27). Owen then goes on to make what has become the most popular statement of the book: “Do you mortify, do you make it your daily work; be always at it whilst you live; cease not a day from this work; be killing sin, or it will be killing you” (27). No Christian is exempt from this duty.
The bulk of the chapter is then divided into six reasons why mortification of sin is so necessary.
First, he notes that we will always have indwelling sin for as long as we are in this world (28). He then goes on briefly to address the dangers of what many would call today perfectionism, which is the belief that perfect obedience can be achieved in this life. He gives two examples of this: 1) those who believe themselves to have obeyed God’s law perfectly or 2) those who simply bend God’s law into conformity to their own hearts (28-29). Yet Owen soundly shows, through Scripture, that “we have a ‘body of death’ (Rom. 7:24), from whence we are not delivered but by the ‘death of our bodies’ (Phil. 3:21)” (29). Since sin, therefore, is our daily reality, mortification must be as well.
Have you ever encountered or believed yourself the sort of perfectionism that Owen describes? Why is it such a dangerous belief?
Second, Owen warns that sin does not merely still lie within us; rather, it labors to act. He states:
When sin lets us alone, we may let sin alone: but as sin is never less than quiet when it seems to be most quiet, and its waters are for the most part deep when they are still, so ought our contrivances against it be vigorous at all times, in all conditions, even where there is least suspicion.29
In other words, sin is always at work to bring about our death, so we must always be at work putting it to death.
In what ways, have you seen sin’s constant activity in your own life?
Are you being diligent today to kill the sin that longs to kill you?
Third, if sin is left unmortified, it will always “bring forth great, cursed, scandalous, soul-destroying sins… Sin always aims at the utmost: every time it rises up to tempt or entice, might it have its own course, it would go out to the utmost sin of that kind” (31). This point gnaws away at the notion of “little” sins. Like Lot with the town of Zoar, we look at our pet sins and say, “Is it not a little one” (Genesis 19:20)? The reality, however, is that there are no little sins. Sin’s wage is death, and it will cease at nothing less. And let us duly note: “There is not the best saint in the world but, if he should give over this duty, would fall into as many cursed sins as ever any did of his kind” (32).
Have you ever witnessed, either in yourself or in another, how a “small” sin quickly grew into a much larger and scandalous sin?
Do you have any pet sins that you refuse to mortify because you believe that they are harmless? Ask the Spirit through the Scriptures to reveal any such sins that you may not presently see.
Fourth, we have been given both the Spirit and our new nature “to oppose sin and lust” (32). He cites Galatians 5:17 as a support for this reason: “For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for they are opposed to each other, to keep you from doing the things you want to do.” The Spirit’s indwelling is our greatest weapon against our indwelling sin, and we would be the greatest of fools to bind the Spirit’s natural work of empowering us to mortify sin (33). Furthermore, Owen ends this point by declaring, “Not to be daily mortifying sin is to sin against the goodness, kindness, wisdom, grace and love of God, who hath furnished us with a principle of doing it” (33).
Why are the Spirit and our new nature in Christ opposed to sin?
Why is the neglect of mortification a sin itself?
Fifth, neglect of mortification causes grace to wither, lust to flourish, and our hearts to deteriorate (33). He offers a rhetorical question that is, sadly, only too relatable:
See we not those, whom we knew as humble, melting, broken-hearted Christians, tender and fearful to offend, zealous for God, and all his ways, his sabbaths and ordinances, grown, through a neglect of watching unto this duty, earthly, carnal, cold, wrathful, complying with the men of the world and things of the world, to the scandal of religion, and the fearful temptation of them that know them?34
Why does sin cause grace to wither?
Sixth, mortification is our duty as servants of Christ as we pursue holiness. “Let not that man think he makes any progress in holiness, who walks not over the neck of his lusts” (34-35).
Why does our pursuit of holiness require the mortification of our sin?
Finally, while Owen acknowledges the abundance of religiousness in his own day, he laments how few seem actually to mortify their sin. He powerfully notes:
If vain spending of time, idleness, unprofitableness in men’s places envy, strife, variance, emulations, wrath, pride, worldliness, selfishness, be badges of Christians, we have them on us and amongst us in abundance. And if it be so with them who have so much light, and which we hope is saving, what shall we say of some who would be accounted religious, and yet despise gospel light, and as for the duty we have in hand know no more of it than what consists in men’s denying themselves sometimes in outward enjoyments, which is one of the outmost branches of it and which yet they will seldom practice?36
He then presents two great evils that derive from such unmortified professors (that is, those who profess to be Christians but do not mortify their sin). First, they do evil to themselves by numbing their conscience to sin all the way into damnation. They sin without guilt and use the grace of Christ as an excuse to continue sinning. Second, they do evil to others through deception. Because they look religious, others are drawn to compare themselves to them, using their ungodly conduct as a standard for the Christian life. They “talk spiritually, and live vainly”, and others follow after them (37).
What are unmortified professors, and why does Owen lament them?
 Unlike other Puritans such as Thomas Watson or Thomas Brooks, John Owen not usually known for his pithy one-liners, but this is a good one!
Note: page numbers are for this edition of the book.