I think I used to think of spiritual warfare as mostly fighting against the powers of darkness for the souls of unbelievers and against the culture for the glory of God’s name and reputation. But more and more, I see it as the fight of faith: the personal fight against sin, the fight for growth, maturity, and holiness. The fight of faith, not of the faith — the fight of my faith, personal faith. Faith and trust in God’s promises. Faith that all he does is for my good and his glory. Faith that he will finish the good work he began in me. Faith that he will never leave me nor forsake me. Faith in his perfect, steadfast love and unchanging character.
This is what John Piper has in mind here. As John Owen said, “Be killing sin or it will be killing you.” Note the list of the kinds of sins we are to fight against daily (emphasis added). Quite a convicting list.
Lent or no Lent, not doing some things you feel like doing is the daily pattern for the disciples of Jesus. Yes, daily. “If anyone would come after me, let him deny himself and take up his cross daily and follow me” (Luke 9:23)….
This is normal, daily, Christian warfare. Only saints delight in the law of God at their depths. Here is how they talk: “I find it to be a law that when I want to do right, evil lies close at hand. For I delight in the law of God, in my inner being, but I see in my members another law waging war against the law of my mind” (Romans 7:21–23).
A war indeed. Daily. “The desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do” (Galatians 5:17).
And make no mistake, sexual desires are not our most deadly desires that need daily denial. Anger, resentment, fear of man, discouragement (yes), self-pity, self-promotion, hardness, envy, moodiness, sulking, indifference to suffering, laziness, boredom, passiveness, lack of praise, lack of joy in Jesus, disinterest in others, etc. These need daily killing (Romans 8:13).