Flu season is in full effect. We’re now in the middle of the timeframe where flu activity is at its peak. The Center for Disease Control estimates that the flu hospitalizes 200,000 and kills 36,000 people every year.

Imagine for a moment that you start to feel flu-like symptoms and decide to go to the doctor. He diagnoses you with the flu and prescribes medicine or action steps to help you feel better.

Let’s say your symptoms aren’t too severe, and so he recommends rest and hydration to allow your immune system to kill the virus. He says, “If you rest at home and drink plenty of fluids, you will get better. If you don’t, the flu will progressively get worst.” But instead of following the doctor’s orders, you don’t keep your body hydrated and stubbornly go to work the next day. It’s guaranteed that you will get worse and pass the virus to your co-workers.

All of this could have been avoided if you had obeyed the conditions of your doctor’s orders. But because you didn’t, you’ve placed yourself and others at risk.

The Apostle’s Prescription for Sin

In Romans 8:13, the apostle Paul prescribes medicine to Christians to kill the disease called sin that dwells in all of us. His prescription also has conditions: “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.”

In “Overcoming Sin and Temptation,” John Owen notes that conditionals, such as “if,” can denote two things: the uncertainty of something promised or the certainty of the coherence and connection between the things spoken of.

For example, a person might say, “If I receive one billion dollars, I will donate one- hundred million to my church.” This person is uncertain that they will actually receive the money and therefore can’t guarantee that they will be able to give such an amount to their church.

John Owen assures us that this is not the intention of the apostle’s expression. He concludes that the apostle’s condition is like that of our imaginary doctor: “If you rest at home and drink plenty of fluids, you will get better. If you don’t, your will get progressively worst.”

The apostles prescription in Romans 8:13 provides a concrete link between the killing of the deeds of the body and life. Owen reminds us that this connection,

Is not [a matter] of cause and effect properly and strictly — for “eternal life is the gift of God through Jesus Christ” (Romans 6:23) — but of means and end. God has appointed this means for the attaining of that end, which he has freely promised. Means, though necessary, have a fair subordination to all end of free promise. A gift, and procuring cause in him to whom it is given, are inconsistent. The intention, then, of this proposition as conditional is that there is a certain infallible connection and coherence between true mortification and eternal life: if you use this means, you shall obtain that end; if you do mortify, you shall live (Overcoming Sin and Temptation, 45).

In other words, Owen helps us see the mortification of sin by the Spirit is the means or action carried out by those who have been freely given the gift of eternal life through Jesus Christ. We don’t kill sin in order to live, but we kill sin because we have been freely given eternal life. Therefore, if we kill sin, we are alive.

Time Doesn’t Kill Sin

Sanctification has slowly become a passive act for many of us. We binge on entertainment, scroll endlessly on social media, neglect prayer, and put off Bible reading hoping that over time we will miraculously become holier. The problem is that Paul doesn’t say time makes us holier. He never writes, “If you get older, you will live.” Old age doesn’t kill sin. If you make peace with your sin and hope that time or age kills it, it will only grow more twisted and perverted.

The Christian’s sanctification is active, not passive. We are called to be active participants in this war against the flesh. But we do not wage war by the flesh; we wage war by the Spirit.

But what does “by the Spirit” mean? John Piper offers these three steps to killing sin by the Spirit.

1. Set Your Mind on the Things of the Spirit

Piper points us to Romans 8:5–6 and explains that,

Putting to death the deeds of the body by the Spirit involves “setting the mind on the things of the Spirit.” You don’t just look at the temptation and say no. You do that! But if you are going to put it to death by the Spirit, you have to do more: you direct your mind, your heart, your spiritual focus another way, namely to the “things of the Spirit.”

2. Set Your Mind on the Words of God and the Realities They Stand For

In order to direct your mind, heart, and spiritual focus to the “things of the Spirit,” you must know what the “things of the Spirit” are. Piper points to 1 Corinthians 2:13–14 and concludes that the “things of the Spirit” are the words of God:

To put to death the deeds of the body “by the Spirit” is to “set your mind on the things of the Spirit,” which we now see means embracing the words of God (and the reality they point to) spoken by his inspired spokesmen.

This is especially significant because “the word of God” is called “the sword of the Spirit” in Ephesians 6:17. And swords are used for killing. And that is what we are to do “by the Spirit” in Romans 8:13. Kill the deeds of the body by the Spirit, that is by fixing your mind on “the things of the Spirit,” that is, by welcoming and embracing the “word of God” in your mind and heart, that is, by taking the Sword of the Spirit which is the deadly sword for sin-killing.

3. By Hearing with Faith, Not Works of the Law

Finally, Piper poses the question, “What do you do to bring the power of the Spirit by the word of God into vigorous, sin-killing action?”

To answer the question, he turns to Galatians 3:5: “Does he who provides you with the Spirit and works miracles among you, do it by the works of the law, or by hearing with faith?” and explains that “the Spirit is supplied to us for the miraculously mighty killing of sin not by works of the law but by ‘hearing with faith.’”

Conditions Can Be Good News

What if you went to the doctor and he told you that there is nothing he can prescribe? Instead, you have to wait and hope your condition improves. Would this be good news? What if he told you there was nothing he could do and that you could never have a full and vibrant life as long as you lived? Would this be good news?

The temptation is to look at the gracious conditions in Romans 8:13 and lose hope. But this is sadly misguided. God has prescribed and freely given us a gracious gift to kill our sin and live full, robust, God-glorifying lives. He’s given us the Spirit and promises that if we wage war against the flesh by the Spirit, we will live. This is good news.