Be killing sin or it will be killing you. -John Owen
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
I was rebuked yesterday, reminded that the repetition of Christian-sounding phrases doesn't always communicate exactly what I think they do. In meeting with someone for counseling, I encouraged them to "kill your sin!" only to be met with questions and misunderstanding. You see, it turns out that just saying "kill your sin" doesn't actually tell anyone what that means. It's not as if sin is a physical thing that can be taken outside and shoved off a cliff. So what does it mean to kill sin?
**We kill sin when we refuse to do it **
"If anyone would come after me, let him deny himself and take up his cross daily and follow me." (Lk. 9:23) The Christian life is one of self-denial, of saying no to the things we sinfully desire. The killing of sin begins and ends with this: saying no to yourself. Denying yourself the pleasure of that lustful look or refusing to wallow in the delights of your anger - this is the sum and substance of what we mean when we talk about killing sin. It's the anti-Nike: just don't do it.
_We kill sin when we refuse to feed it _
"Keep your heart with all vigilance, for from it flow the springs of life." (Prov. 4:23) If we are to be successful in saying no to our sinful desires, we must also be working to starve those same desires. While we may never be able to fully starve them into submission before we get to heaven, we can greatly weaken them with what we choose to put into our minds and hearts. If we're honest, there are things we choose to do that, while they may not be sinful in and of themselves, feed the beast of temptation. Staying up late may feed the beast of poor Sabbath-keeping. Going to certain places at night may feed the beast of drunkenness. You get the point: figure out what the beast is and starve it!
We kill sin when we pray against it
"Who will deliver me from this body of death? Thanks be to God through our Lord Jesus Christ!" (Rom. 7:24-25) Killing sin is a spiritual business in that it requires the aid of the Holy Spirit to be successful. If we line up on the battlefield against sin under our power, defeat is usually certain. But if we prayerfully go to battle by praying often (daily, hourly, minute-by-minute when needs be!), we line up behind Christ and His Spirit. We march toward a certain victory when we fight on our knees.
**We kill sin when we pursue the opposite **
"Finally, brothers, whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is lovely, whatever is commendable, if there is any excellence, if there is anything worthy of praise, think about these things." (Phil. 4:8) Sin is parasitic, always feeding on something good and producing something bad through it. Were it not for the good and beautiful, sin couldn't even exist. So part of killing sin is finding those things that sin is perverting and pursuing those with all our energies. Those who steal need to work hard. Those who lust need to love their husband or wife (present or future). Those who enjoy violence need to pursue the knowledge of the Prince of Peace.
Much more could be said. (If you'd like to read great work on this topic, you can't do better than John Owen on the Mortification of Sin.) But hopefully this is enough for a simple and clear reminder.