The world in its fallen state, opposed to the things of God, daily attempts to take our focus off of our Creator. It tempts us to adopt its ungodly affections and actions. If we are not vigilant, we will succumb to this enemy.
Yet, not only must we fight the world as we grow as Christians, but we must also fight the flesh. Many Christian thinkers have warned us against the lust of the flesh, and Augustine illustrates this lust in a famous story from his Confessions. He tells about an episode from his youth when he stole some pears from a neighbor’s orchard simply for the thrill of the theft. He did not steal because he was hungry—which we might understand even if we do not approve—but simply because the pears were there. There was no rational explanation for the sin except the love of sin. That is the lust of the flesh taken to the extreme, that is, doing evil when we reap no tangible benefit.
We must fight against the lust of the flesh because of our fallen condition. True, God makes us new creatures in Christ, giving us a real affection for godliness. Until we are glorified, however, we still deal with the remnants of our fallen natures. Sometimes we want to do what is good and yet do the opposite (Rom. 7:7–25). Conversion changes the direction of our lives, but sometimes we fall back into the old ways of sin and death. Romans 8:1–11, therefore, exhorts us to put the flesh to death and to walk by the Spirit. The idea here is not that we should disdain the physical world or hate everything that might bring us bodily pleasure. Instead, the war is a spiritual one, a battle between who we are in Christ as God’s holy people and who we were in Adam as enslaved to destruction. We are free to enjoy God’s good creation; the problem comes when we love the creation more than the Creator.
Fighting against our flesh may require us to say no to some of the things that the world offers us, but it does not consist in an asceticism that denies us pleasure altogether. Some Christians have thought the path of holiness is avoiding all movies, all dancing, all alcoholic beverages, and other such things. But the real battle against the lust of the flesh in our sanctification entails the much harder work of saying no to envy, covetousness, discontentment, unjust hatred, and other inward affections that are much more difficult to avoid and to reject than external things.