Be Killing Your Sin, part 1

It’s been said that books change lives. As someone who is an avid reader (or, who at least tries to be), I believe that’s true, but I also believe it’s not just books that change lives; sentences change lives.

Sentences have the ability to stick with you as you go. We may remember the main idea of the book, we may remember the main points of the book, we may even remember the flow of the argument of a book, but a good sentence tends to stick with us in more powerful, life-changing ways.

The two go hand-in-hand, of course. A good book—the kind that you want to return to, or keep nearby on your shelf, or have extra copies to give away—almost always contains those great sentences that stay in your mind for months or even years to come.

One of the sentences that has done that for me was written 365 years ago in a book called The Mortification of Sin by the Puritan pastor and theologian John Owen (note: see end of post for link). I first read the book around 15 years ago, and the life-changing sentence from that book has regularly come to my mind, and impacted my life, ever since. That sentence is this:

Be killing sin, or it will be killing you.

John Owen

I cannot think of much advice that is more needed, more practical, more urgent, than that.

The Scripture warns us clearly: sin is nothing to take lightly, because sin seeks to destroy us. Peter alerted us to the fact that we’re involved in a war. “The passions of the flesh … wage war against your soul” (1 Peter 2:11), he wrote, later adding that “your adversary the devil prowls around like a roaring lion, seeking someone to devour” (1 Peter 5:8). Therefore, the Christian cannot make peace with sin. Instead, God on more than one occasion tells us not to manage sin, but to put it to death.

Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.

Colossians 3:5

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.

Romans 8:13

How do we do that? That’s what we’ll be considering over the next month on the Pastors Blog. Next week, we’ll consider the one thing without which it is impossible to kill sin. On August 16, we’ll look at the commands to “put off” sin and “put on” righteousness. The following week will be focused on encouraging us to persevere in the fight, and, finally, on the last Monday of August we’ll consider the role of others in helping us fight sin.

In the meantime, a great first step would be to begin searching your own heart. What sin are you treasuring right now?  Or, maybe you haven’t allowed yourself to go into open sin, but is there a temptation that you’re allowing to remain present in your mind? Is there something that you repeatedly fall into, that you know is sinful, but that you cannot seem to beat? Is there a sin that you’ve just resigned yourself to the thought that it will always be there in your life?

Two helpful passages to consider are found in Colossians 3 and Galatians 5. Read these over and ask yourself: do I see any of these in me?

Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry. On account of these the wrath of God is coming. In these you too once walked, when you were living in them. But now you must put them all away: anger, wrath, malice, slander, and obscene talk from your mouth. Do not lie to one another, seeing that you have put off the old self with its practices and have put on the new self, which is being renewed in knowledge after the image of its creator.

Colossians 3:5–10

Now the works of the flesh are evident: sexual immorality, impurity, sensuality, idolatry, sorcery, enmity, strife, jealousy, fits of anger, rivalries, dissensions, divisions, envy, drunkenness, orgies, and things like these. I warn you, as I warned you before, that those who do such things will not inherit the kingdom of God.

Galatians 5:19–21

These are the areas that we want to begin to fight against, to seek to put these to death in our lives. The work isn’t easy, but it’s necessary, and God has given us what we need for the battle.


There are multiple modern editions of Owen’s The Mortification of Sin. I do highly recommend it and believe that you benefit greatly from reading it along with this series of blog posts. The version that I prefer is found in the book Overcoming Sin and Temptation, edited by Kelly Kapic and Justin Taylor. This edition contains two other works by John Owen on the same theme. I have also benefited from the abridged version by Richard Rushing in the Puritan Paperback series.


Bert Watts has served since December 2016 as the Senior Pastor at Mountain Creek Baptist Church, where he has been on staff since 2012.

Photo by Jonathan Kemper on Unsplash