As the previous president and current chancellor emeritus of The Master’s University, I have spent a lot of time with young people. And one of the things I fear most for them is that, during the years of their youth, they will train themselves to sin.

Whether we know it or not at the time, the habits we form as young adults will become stubborn patterns later in life. It’s during the college years that we develop what the writer of Hebrews calls “besetting” or “entangling” sins (Hebrews 12:1). These are the sins that have become familiar to you, and perhaps are so habitual that you no longer even recognize them for what they are. This sort of sin can sometimes feel impossible to break.

The tragic thing is that habit and familiarity do nothing to lessen the actual horror of sin. All of our sins, even the ones we don’t recognize, are the sins that nailed Jesus Christ to the cross. They are the sins for which He died. And yet we witlessly, ignorantly, and sometimes even willfully, continue to live in these same sins.

It is easy for us to look at the familiar words of Hebrews 12:1, with its warning about how easily sin entangles us, and be numb to the real danger that the writer is describing. If a student at TMU develops a habitual sin here on campus, in an environment rich with biblical teaching and Christian friendship, how much more will they struggle with that same sin when they go back home for the summer or when they graduate? Once sin has a foothold, it is difficult to escape. Because of this, most people will have certain sins that they must battle their whole lives because certain habits were cultivated in youth.

If you are going to live the Christian life well and run the race with endurance, you have to deal with your entangling sins. And the first step of battling these sins is understanding why they ensnare us so easily.

1. Sin has power because your flesh is unredeemed.

When God saved you, your spirit was redeemed. You are, on the inside, a new creation. Your flesh, however, has not been redeemed, and this is why sin still has a foothold in our lives.

By “flesh,” I don’t just mean our physical bodies. I mean our humanness — the way we act, think and feel. Our wills, emotions and bodies are part of our unredeemed flesh, and it is in these areas that sin continues to have power. This is why Paul wrote, “O wretched man that I am! Who will deliver me from the body of this death?” (Romans 7:24). Paul saw his flesh like a decaying corpse that he was strapped to and couldn’t escape. It was repulsive to him because the influence of his flesh was in opposition to the Spirit (Galatians 5:17).

Sin has great power in our emotions. It has great power in our will. And until our bodies are redeemed, we are highly vulnerable to sin’s influence. That’s why the Bible talks about staying as far away from sin as we possibly can, because it so easily finds its way into our unredeemed flesh.

2. Sin has power because it is inside you.

We would like to believe that sin is an enemy that exists outside of us — something we can see coming long before it gets to us. But in truth, sin is very close; it is actually inside of us. Jeremiah 13:23 says, “Can the Ethiopian change his skin? Or the leopard change his spots?” And the obvious answer is no. The second part of the verse continues: “Then you also can do good who are accustomed to doing evil.” And the point is that it is natural for us to sin because it is inherent to our nature. Sin is deep within us. “The heart,” says Jeremiah, “is more deceitful than everything else and desperately wicked” (Jeremiah 17:9).

Whether you are alone at home or in the midst of a congregation on Sunday morning — wherever you are — your sin is also there. You can never run far enough to get away from it. Being around the right people and being in the right environment can certainly make the battle easier, but it will never eliminate the sinfulness of your flesh.

3. Sin has power because it is hard to spot.

Somebody asked me some years back if I preach sermons with a pure motive. And my answer to that question was, “I don’t know.” I would like to think that every time I stand up to preach the Word of God, I do it with an absolutely pure motive to glorify God, and not with any motive to bring attention to myself, to gain a reputation or to be thought of as virtuous. But I can’t know myself well enough to say definitively that my motives actually are pure.

Sin is so entangled in what I am that I cannot isolate it; it runs that deeply and that pervasively. I don’t know whether I’ve ever had an absolutely pure motive that lasted very long, because sin infects all my duties. It infects all my ministries. It is tangled up in all my motives. It dampens and wounds all my purposes and all my good intentions, and it even crowds in on the very acts of obedience and worship that I endeavor to express to God.

If sin is so strong, then, what do we do? The Bible tells us that we must lay aside this entangling sin, even in spite of how powerful it is. In the next post we will begin looking at the weapons God has given us for this fight.

This post is based on a sermon by Dr. MacArthur. In addition to serving as the pastor of Grace Community Church and the voice of Grace to You, Dr. MacArthur is the chancellor of The Master’s University in Santa Clarita, Calif. You can learn more about TMU at masters.edu.