“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 ESV

Lamentably, the concept of fighting sin has been neglected in evangelicalism today. Not as a whole, of course, but a large part ignores this command or labels it legalistic.

This should not be the case. The Apostle Paul unequivocally told us that if we do not fight sin—if we do not “by the Spirit put to death the deeds of the body”—we will die. We will not make it to Heaven. Of course, this is not saying we fight sin in order to be saved; rather, we fight sin because we are saved.

Fighting sin is an essential, daily part of the Christian life.

But how do we fight sin? Do we just try to white-knuckle our way out of temptation? How do we push back? These are questions that every Christian should ask. They are very important.

Sin Needs to be Fought

First, let’s admit that this battle is necessary. Combatting sin is an unavoidable aspect of a Christian’s life (just look at Paul’s fight in Romans 7). It is not optional, but a command. As people who have been born again, we should desire the fight. Fighting sin, though difficult and wearisome, should be something every Christian is ready for. Sin is unfailingly “crouching at the door” (Gen. 4:7), so we must be ready to attack.

This fight needs to be fought.

If we neglect to fight sin; if we turn our backs on sin, it will pounce on us—and destroy us. When sin “is allowed to grow, it gives birth to death” (Jms. 1:15 NLT). We cannot allow sin to grow! As John Owen, author of Mortification it Sin, once famously said: “Be killing sin or sin will be killing you.”

These are strong words from the famous Puritan, but make no mistake: he is right. This is the exact point of Romans 8:13. If we do not strive to kill sin, sin will strive to kill us.

There is a very important component to this discussion that we must all understand. The sin we are commanded to kill is not something external; it is within us. It is a part of us. Part of the Christian life is to actively engage in warfare with our old self. Because we have been made new creatures in Christ (2 Cor. 5:17), we have an obligation to kill the sin that still resides in us!

So how do we actually do that?

Fight the Promises of Sin with the Promises of Christ

Do we resist temptation by sheer power of our will? Do we just have to muster up the strength to keep saying “No!” or do we seek refuge in believers around us? Do we simply white-knuckle it?

Part of the problem with Christians who continue to struggle fighting sin is because they are relying on their own strength. We will not kill sin on our own strength. That is impossible.

So, how do we fight it? John Piper once said that,

“Saying ‘no’ will not suffice. You must move from defense to offense. Fight fire with fire. Attack the promises of sin with the promises of Christ … We must stock our minds with the superior promises and pleasures of Jesus. Then we must turn to them immediately after saying, ‘NO!’”

Simply saying “no” to sin will do you no good. We have to be active, not passive. In some circumstances, to actively fight sin means to flee from it (1 Cor. 10:14; 1 Cor. 6:18; 2 Tim. 2:22; many more). We have to always be on the lookout. As Piper said, we “attack the promises of sin with the promises of Christ.” When we feel tempted, we must remind ourselves of Christ’s promises, and believe that the satisfaction He brings us is infinitely superior than any satisfaction sin can bring.

This is the only way you can truly kill sin in your life. Willpower and determination won’t do it, but meditating on the promises of Jesus will!

Of course, this doesn’t mean we don’t also use practical steps to slay sin. We still need to employ practical ways to shield ourselves from sin.

Grant Castleberry, the Discipleship Pastor at Providence Church in Frisch, TX, and Teaching Fellow for Reformanda Ministries, said this in regards to fighting sin,

“The way to fight sin is two-fold:

1. Remember who you are in Christ–that Hid death to sin is your death to sin and you are no longer enslaved (Rom. 6:1-12).

2. Take radical measures by eliminating both temptations and opportunities to sin (Rom. 13:14).”

Taking radical measures against sin by eliminating the opportunity sin is imperative. Do we fight sin by delighting in the promises of Christ or do we fight sin by “eliminating both temptations and opportunities to sin?” Yes.

And, above all else, this glorifies God. It glorifies Him when we look to His promises in order to slay our sin. How so? It shows that we believe His promises, His satisfaction, and His glory is far superior than any sinful thing the world can offer.

So, friends, remember: stop aiming to kill sin by your own strength. It won’t happen. Do you believe that the promises of Jesus are more satisfying than sin? If so, meditate on them and you will, I hope, begin overcoming sin far more than you used to.