3 Reasons Why You Must Mortify Sin in Your Life

Mortification of sin is not often discussed openly in churches these days. It sounds very Puritan. In a sense, it is. If anyone had a deep understanding of the reality of sin and its impact, it was the Puritans. What’s even more unfortunate is the dilution, perversion, and complete loss of the principle itself. Absence of the mortification of sin in the contemporary church, however, has not removed the principle from Scripture.

“Put to Death What Is Earthly in You”

In his letter to the Colossians, Paul deals with the dynamic of our new nature versus the combative presence of the old:

If then you have been raised with Christ, seek the things that are above, where Christ is, seated at the right hand of God. Set your minds on things that are above, not on things that are on earth. For you have died, and your life is hidden with Christ in God. When Christ who is your life appears, then you also will appear with him in glory. (Col. 3:1-4)

The first four verses of chapter 3 talk about our new identity. It’s the substance of what life in Christ is. Paul frames his entire argument with “If you have been raised with Christ.” In other words, if we in fact have been made alive, these are his instructions with regard to remaining sin.

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. (Col. 3:5-8)

When Paul is laying these things out, he is not doing it in a way that is encouraging hypocrisy. He is not saying, “I want you to stop doing these things only so that you can appear moral and pious.” He’s saying, “I want you to put these sins to death, because as Jesus said, you are to be holy.” The sin in your life needs to be rendered completely helpless with regard to influencing your living and your relationship to God. Here are three reasons Christians work to mortify sin:

1. God’s wrath will be poured out on all unrighteousness. 

When we mortify sin in our bodies and minds, we imitate the way our heavenly Father has mortified the wages of our sin through Christ. 

The reason Christians struggle so deeply with the presence of unconfessed and unrepentant sin in their lives is because they know God sees it, they know what God is capable of toward it, and they know they are acting outside of their new identity. 

Jesus did not die to allow God to shrug off our sin; he died to justify who we are before the holiness of God. The theologian R. C. Sproul says this about sin:

Sin is cosmic treason. Sin is treason against a perfectly pure Sovereign. It is an act of supreme ingratitude toward the One to whom we owe everything, to the One who has given us life itself. Have you ever considered the deeper implications of the slightest sin, of the most minute peccadillo? What are we saying to our Creator when we disobey Him at the slightest point? We are saying no to the righteousness of God. We are saying, “God, Your law is not good. My judgement is better than Yours. Your authority does not apply to me. I am above and beyond Your jurisdiction. I have the right to do what I want to do, not what You command me to do. (R. C. Sproul, The Holiness of God, p. 116)

If God is the ruler of this universe, there is nothing about sin that he, even as our Father, flagrantly dismisses. If that were true, there would be no need for sanctification. Rather, because sin is so grievous, particularly in the life of those who have new life in Jesus, God has set forth by way of his Spirit his sanctifying work. Apart from God’s work, we would never grow away from sin’s pull.

2. A Christian knows that these are the things from which he was saved. 

We need to remember what sin has done versus what Christ has done for us. Jesus’ sacrifice not only justifies us before God, but it sets us free fromthe shackling effect of sin now:

Do not present your members to sin as instruments for unrighteousness, but present yourselves to God as those who have been brought from death to life, and your members to God as instruments for righteousness. For sin will have no dominion over you, since you are not under law but under grace. (Rom. 6:13-14)

Often, we fail to kill sin because we forget that Jesus’ sacrifice not only set us free from the wrath of God that is to come as a result of unrighteousness, but it has also set us free from the rulershipof that sin.

Why else would Paul direct his instruction to us? He’s saying, “Do whatever you need to do. Even if that means recruiting a brother in Christ to help demolish the sin you have in your life right now and what will come in the future! It has no dominion over you! It is not your king, and if you claim to follow Jesus and you continue to harbor your sin, then you are professing that you are serving two masters—God, and that particular sin.”

Jesus goes even farther by telling his hearers to cut off their hand and pluck out their eye if it falls to the temptation of sin:

“Woe to the world for temptations to sin! For it is necessary that temptations come, but woe to the one by whom the temptation comes! And if your hand or your foot causes you to sin, cut it off and throw it away. It is better for you to enter life crippled or lame than with two hands or two feet to be thrown into the eternal fire. And if your eye causes you to sin, tear it out and throw it away. It is better for you to enter life with one eye than with two eyes to be thrown into the hellof fire.” (Matt. 18:7-9)

Jesus is presenting a principle that we often overlook. Using hyperbole, he’s saying if the car you are driving is going to cause the wreck, trade it in. Stop driving it. Remove it from the scenario. He shockingly tells how we must radically reject whatever may lead us into sin, when he says to cut off our arm and pluck out our eye if it is the infirmity that is going to give way to temptation. Of course, he’s not teaching us to literally destroy our bodies, but he uses this radical illustration to show how much we are called to destroy sin and temptation in our lives.

3. We mortify sin because it does not exist in our Savior and will not exist in us. 

If you are in Jesus and you are harboring sin, you are preaching heresy every single day. Why? If you and I are being made more into the image of Jesus and we are protecting sin in our life rather than killing it, then we are saying, “This is part of who my Jesus is.” The very definition of heresy is misrepresenting the nature of God!

Our very representation of God is what is at stake. The only reaction that we should have for this kind of behavior is swift and violent. John Owen said, “Be killing sin, or it will be killing you” (The Mortification of Sin, [Banner of Truth, 2004], p.9). 

There is nothing about your sin that wants to help you along this journey, dear friend. It wants you to be as lame and crippled as you can possibly be as it sucks the very life out of you. It wants the world around you to see an unclear picture of Jesus—one that is insufficient, one that is weak and unable to save men’s souls. That’s what your sin wants.

In a Tabletalk article, Sinclair Ferguson, an author and pastor that I respect dearly, gives four points on dealing with sin in our lives:

  • Learn to admit sin for what it really is.

  • See sin for what your sin really is in God’s presence.

  • Recognize the inconsistency of your sin.

  • Put sin to death.

Refuse it, starve it, and reject it. You cannot “mortify” sin without the pain of the kill. There is no other way.

When you fall into the temptation to keep doing what you are doing, and you know it is not godly, you are working to keep sin alive. You are proclaiming to the world around you that the gospel is inconsistent, and that God is okay with it. That’s not the gospel! If you are truly a child of God, 1 John 3:9 is clear that you “cannot keep on sinning.” This doesn’t mean that you will not struggle with sin, but it should not be an easy habit for you.

This is not because you have some sort of magical ability of your own to somehow deconstruct and dismantle sin, but it means that you have been justified before a supernatural and Holy God, whose design for you is to enter into eternity blamelessly and without blemish.

Sin is the apex predator of our joy and faithfulness to God. Left unchecked, it can destroy you. Sportsmen understand the need for predator control. It protects the helpless. It supports the populations of animals that are more desirable. There is no greater challenge to us than the sin that attempts to rob us of our joy in Christ. But through Christ, by the power of his word and Spirit, it can be overcome, for it is God who works in you both to will and to work for his good pleasure (Phil. 2:13).

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