Even for Christians, the temptation to sin remains an ever-present danger. Mortifying our sin is thus a battle we must earnestly wage, as John Owen wisely said, “Be killing sin, or it will be killing you!” But how do we engage this mortal enemy? The Apostle Paul gives four points of wisdom in Romans 8:13-14: First, stop paying the flesh, because you owe it nothing. Second, if you’re fighting sin, know that you’re dead to sin and alive to God. Third, do it by the Spirit—not by asceticism or personal discipline—but by the power of sanctifying grace. And if you do so, you will live! Killing sin doesn’t get you right with God; it shows that you are right with God because His justified people always bear fruit.