Romans 8:12-13

Therefore, brothers, we have an obligation--but it is not to the sinful nature, to live according to it. For if you live according to the sinful nature, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live...

Paul’s teaching on sanctification always does two things at the same time. It always energizes us to godliness and assures us of salvation. And if a teaching on sanctification fails to do both of those things at the same time, it’s not Pauline, and it’s not Biblical. Paul always energizes us to growth in grace, and he always assures us of salvation.

Paul says that Christians are under obligation not to live the way someone lives apart from Christ, but to live a different way. We have no debt or obligation to the flesh, because our new life didn’t come from the flesh. It’s the work of God that has given us this new life, and therefore, we ought not to live for the flesh or for its goals. We are under obligation to God not to live according to the principles and aims of a corrupt human nature. Paul is telling us in v12 that we ought to grow in grace, because we are in debt to God. We are obligated to God because of the indwelling of the Holy Spirit. We often say that in the Christian life the great motive of the Christian life is gratitude. We don’t obey in order for God to love us; we obey because He has loved us savingly in Jesus Christ. But Paul’s not bringing before us a motivation of gratitude; he’s actually bringing a motivation of obligation. Paul’s point in v12 is important because of the unbreakable link between sin-killing and death on the one hand, and between killing sin and life on the other.

And in v13, we see a bit of a paradox: “Be killing sin or it will be killing you.” Kill sin or it will kill you. Paul says that sinful living is always inseparably linked to death. But he also says that putting sin to death is inseparably linked to life. Sinful living leads to death, putting death to sin or putting sin to death always leads to life. It’s paradoxical. Jesus in Matthew 16:25 said a similar thing: “For whoever wishes to save his life will lose it; but whoever loses his life for My sake will find it.” It’s paradox. But how do we kill sin?

Paul here is indicating that the believer is always at work in sanctification. The very phrase “you are putting to death the misdeeds of the body” indicates that. The indicatives of grace never produce passivity in the true believer. They produce a strong, grace-dependent, faithful activity on the part of the believer. However, even with his emphasis on our activity, Paul makes it clear that the deeds of the flesh are being killed by the Spirit. It’s not “me versus the flesh,” it’s “the Spirit in me versus the flesh.” Who kills sin? You or God? Who gets the glory for it? You or God? Or do you share both the responsibility and the glory, since you both have a role?

When Paul says, “putting to death the misdeeds of the body,” he doesn’t just mean physical sins. He means those practices that characterize the sinful nature, which are often expressed in a physical way. But it’s not just actions of the body. He’s talking about all the characteristic practices of the sinful nature. When he says, “by the Spirit,” he’s reminding us that killing sin, that warring against sin, is something that flows from the power of the indwelling Holy Spirit through faith and not by works of law. And when Paul speaks of life at the end of v13, he’s referring to that fullness of eternal life that the saints enjoy in fellowship with God. Your killing of sin is the effect of having life; dying is the effect of sin’s killing you.