Know Your Enemy: The Danger of Underestimating and Accommodating Sin

This blog post was adapted from a sermon that I gave at the Harvard Avenue Student Ministry‘s Winter War Games event on Saturday, February 1, 2014.

Key Texts: Judges 2:11-17; Romans 8:5-13

What is the greatest enemy of the Christian? No doubt there are many enemies we face as believers: Satan, demonic powers, the temptations of the world, and sin just to name a few. Each of these is dangerous and something we should be on guard against.

However, Scripture tells us consistently that our greatest enemy isn’t Satan. It isn’t the demons. The greatest, most dangerous enemy for any Christian is his or her flesh. J.C. Ryle realized this: “Sin and the devil will always find helpers in our hearts.” My greatest enemy is myself. Your greatest enemy is yourself. From the day we are saved until the day we die, our new spiritual nature will be at odds against our old sinful flesh nature. Our hearts are idol factories! (Martin Luther) We must recognize this enemy that lives within us and take it seriously or it will overcome us.

In 1886, Robert Lewis Stevenson published The Strange Case of Dr. Jekyll and Mr. Hyde. In the book, the respected Dr. Jekyll has an evil living within him that manifests itself periodically in the form of Mr. Hyde who goes on violent, lustful rampages. At first, Dr. Jekyll is appalled by the actions of Mr. Hyde, but as time goes on, he comes to enjoy the release from morality that his evil side offers.

At one point Dr. Jekyll says, “I had learned to dwell with pleasure as a beloved daydream on the thought of the separation of these elements. If each, I told myself, could be housed in separate identities then life would be relieved of all that was unbearable: the unjust might go his way delivered from the aspirations and remorse of his more upright twin, and the just could walk steadfastly and securely on his upward path doing the good things in which he found his pleasure and no longer exposed to disgrace and penitence by the hands of this extraneous evil.” Thinking he could control the two, he develops a potion that allows him to switch between the good Dr. Jekyll and the evil Mr. Hyde whenever he takes it. However, the more he feeds and enjoys his evil nature, the more it controls him. Eventually, Dr. Jekyll gets to the point where Mr. Hyde takes over at random times and can’t be subdued by the potion. Recognizing that eventually Mr. Hyde will completely consume the once honorable Dr. Jekyll, Jekyll pens a note that ends with “I bring the life of that unhappy Henry Jekyll to an end” and commits suicide.

See how deadly our indwelling sin is? It wars against us in our pursuit of holiness. It tries to take us captive, lull us to sleep, and lead us away from the God who redeemed us from the curse. It promises temporary relief and pleasure, and the more we accommodate it like Dr. Jekyll did, the stronger it grows until it eventually kills us.

Let’s look at how this played out in the nation of Israel. 

The Warning of Judges

Here’s a brief look at the events leading up to Judges 2:11-17:

  • The book of Exodus recounts God’s deliverance of the nation of Israel from the slavery and bondage of Egypt.
  • After crossing the Red Sea on dry ground, Moses and the Israelites cross the desert and come to the edge of the Promised Land. Moses sends 12 spies to spy out the land and give a report. 10 of the 12 spies give a negative report, fearing the people already dwelling in the Promised Land. Their negative report causes the nation of Israel to rebel despite the encouragement to trust God’s promises from the two faithful spies: Joshua and Caleb. (Numbers 13-14)
  • As a punishment for their lack of trust in God’s promise, the Israelites wander around in the desert for 40 years until the whole disbelieving generation, except for Caleb and Joshua, die. They come to the edge of the Promised Land again and God gives them a clear command, promise, and warning in Numbers 33:50-56.
  • Joshua leads the Israelites into the Promised Land and begins to conquer it, driving out the peoples dwelling there and destroying their idols, just as God had commanded. (Joshua 21:43-45)
  • The conquest is incomplete as Joshua’s death approaches. Before Joshua dies, he commands the people to choose who they will serve: God or false idols. (Joshua 24:19-20,23)
  • With Joshua dead, the Israelites continue the conquest of the Promised Land, but fail to drive out all of the people living there. Instead, they accommodate them and let them live among them. This is in direct disobedience to God’s command to drive out everyone and destroy their idols. (Judges 1:19, 27-2:3)

So what is the result of accommodating these people and their false idols? Take a look at Judges 2:10-17. After the godly generation of Joshua passed away, the Israelites forgot about all that God had done for them and abandoned Him in favor of loving and serving the idols of the people they accommodated instead of conquered.

The Bible uses a very strong picture to describe this rebellion: prostitution (v 17). Why prostitution? Because prostitutes become vulnerable in a desperate search of love and approval from their client, who in turn is only using them and doesn’t care about them at all. God’s exclusive covenant people turn away from the one who loved them enough to deliver them from bondage and promise them a new home and instead turn to idols that have no power and want to use them instead of love them. This is spiritual adultery. This is idolatry. And it all happened because the Israelites failed to completely conquer the land that was given to them and destroy the idols that God said would eventually lead them astray. They didn’t take sin seriously.

The prophet Jeremiah uses another picture in Jeremiah 2:5-13 to describe this sin several hundred years later when the Israelites are in slavery again because of their repeated unfaithfulness. Jeremiah is saying that sin is the suicidal preference for the broken wells of idolatry over the river of life flowing from God. We would rather try to save and sustain ourselves by digging wells that are broken and collecting filth, than to simply come and drink from the all-satisfying river of God’s glory.

Accommodating Sin in the Christian Life

So why are we looking at disobedient Israelites? Because we are just like them!

Scripture says that there are two categories of people who live in the world in Romans 8:5-13: those who “live by the flesh” and those who “live by the Spirit.” To be united with God through faith in Christ is to be disunited from our flesh and all other non-gods that fight for our attention. The more we try to reunite with the flesh, the more it consumes us, until like Dr. Jekyll, it totally devours us, turning us into a Mr. Hyde of depraved rebellion against God.

As God’s New Covenant people, Christians all too often underestimate the danger of the sin in their lives, allowing it to remain instead of warring against it as we have been commanded. Instead of “laying aside every weight and the sin that so easily entangles us” (Hebrews 12:1), we compromise and let some sin remain in our life, just like the Israelites let the people of Canaan live among them. Our flesh tempts us to make good things into ultimate things, putting them in place of or on par with God (Romans 1:18-23). Rather than comparing our progress against sin with others, we must compare ourselves to Christ and His holiness. With holiness as our goal, contentment with partial victory over sin is spiritual suicide. We must conquer all of it! As John Owen famously put it, “Be killing sin or it will be killing you.”

Too often, we think we can accommodate smaller, hidden sins as long as we conquer the “big ones.” Like Dr. Jekyll, we rationalize our sin: “I can keep them my Christianity and my sin separate and reap the benefits of both without any consequences.” This is just what our flesh wants: to convince us it isn’t dangerous; that it can coexist with God in our lives. This is a lie. We owe our flesh nothing except for hate and war.

God doesn’t want us to tame our sin; He commands us to kill it! Here’s how John Owen describes it: “When we realize a constant enemy of the soul abides within us, what diligence and watchfulness we should have! How woeful is the sloth and negligence then of so many who live blind and asleep to this reality of sin. There is an exceeding efficacy and power in the indwelling sin of believers, for it constantly inclines itself towards evil. We need to be awake, then, if our hearts would know the ways of God. Our enemy is not only upon us, as it was with Samson, but it is also in us.”

We must view the Christian life as a war. As John Piper once said, “Until you believe that life is war – that the stakes are your soul – you will probably just play at Christianity with no earnestness and no vigilance and no passion and no wartime mindset. If that is where you are this morning, your position is very precarious. The enemy has lulled you into sleep or into a peacetime mentality, as if nothing serious is at stake….There is a mean, violent streak in the true Christian life! But violence against whom, or what? Not other people. It’s a violence against all the impulses in us that would be violent to other people. It’s a violence against all the impulses in our own selves that would make peace with our own sin and settle in with a peacetime mentality….Christianity is not a settle-in-and-live-at-peace-with-this-world-the-way-it-is kind of religion. If by the Spirit you kill the deeds of your own body, you will live. Christianity is war on our own sinful impulses.”

A Call to Conquer

Having a wartime mindset changes the way we approach our Christian life. Just like the nation of Israel was called to completely conquer the Promised Land by trusting that the Lord had already given it to them, Christians are called to completely conquer sin, trusting that it has already been conquered in the death of Christ (2 Corinthians 5:21). There are two aspects of this call to conquer:

  1. “Deny yourself” (Matthew 16:24-26)
    What does it mean to “deny yourself”? It means to deny yourself the short, fleeting pleasures of the world for the everlasting pleasures of heaven.  In other words, we must resist being a spiritual prostitute and trying to dig our own broken wells like the Israelites in Judges and Jeremiah. Self-denial is the (figurative) cutting off of your hand as you reach for a non-god. We must continue to deny our self, our fleshly desires, every single minute, hour, and day until the day we die.
  2. “Fight the good fight of faith” (1 Timothy 6:11-12)
    The “good fight of faith” is this: to recognize, see, and savor Jesus as more valuable than anything else. It is a fight for joy. We saw in Romans that the goal of this fight is to “put to death the deeds of the body” (Romans 8:13). John Piper says of this fight: “Putting to death the deeds of the body by the Spirit – the daily practice of killing sin in your life – is the result of being justified and the evidence that you are justified by faith alone apart from works of the law. If you are making war on your sin, and walking by the Spirit, then you know that you have been united with Christ by faith alone. And if you have been united to Christ, then his blood and righteousness provide the unshakable ground of your justification. On the other hand, if you are living according to the flesh – if you are not making war on the flesh, and not making a practice out of killing sin in your life, then there is no compelling reason for thinking that you are united to Christ by faith or that you are therefore justified. In other words, putting to death the deeds of the body is not the way we get justified, it’s one of the ways God shows that we are justified. And so Paul commands us to do it – be killing sin – because if we don’t – if we don’t make war on the flesh and put to death the deeds of the body by the Spirit – if growth in grace and holiness mean nothing to us – then we show that we are probably false in our profession of faith, and that our church membership is a sham and our baptism is a fraud, and we are probably not Christians after all and never were.”


To close, I must ask you: are you taking your sin seriously? Are you fighting against all of it, or letting some of it hang around in your life? Cornelius Plantinga, Jr. once said, “People tend to make two mistakes when they think about the redeemed life. The first is to underestimate the sin that remains in us; it’s still there and it can still hurt us. The second is to underestimate the strength of God’s grace; God is determined to make us new. As a result, all Christians need to say two things. We admit that we are redeemed sinners. But we also say boldly and joyously that we are redeemed sinners.”

So, Christian: take sin seriously, deny yourself, and fight the good fight of faith knowing that death has died in the death of Christ. He has already overcome the world (John 16:33; 1 John 4:1-6, 5:1-5), so pursue Him alone and not the non-gods our flesh tempts us with. Continue to make war against sin so that we can join Paul at the end of our lives in saying, “I have fought the good fight, I have finished the race, I have kept the faith.” (2 Timothy 4:7)

Learn It. Love It. Live It.

Read more of Lawson’s sermons by clicking here.

Additional Quotes and Resources

  • “The choicest believers, who are assuredly freed from the condemning power of sin, ought yet to make it their business all their days to mortify the indwelling power of sin.” –John Owen
  • “This book (the Bible) will keep you from sin or sin will keep you from this book.” –John Piper’s mom
  • “You are always on duty in the Christian life, you can never relax. There’s no such thing as a holiday in the spiritual realm.” – Martyn Lloyd-Jones


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About Lawson Hembree
Serving others by building brands. Disciple || Marketer || Entrepreneur || Meatatarian Want to continue the discussion or write a guest post? Let's Connect!

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