Imagine the effort required to open up a barricaded door, to then enter a room that you were never intended to see, and finally, to fight a foe that is already dead. How foolish would it be to expend all that effort simply to struggle with a vanquished enemy? And to repeat this exercise over and over . . .
That small exercise in imagination is my feeble attempt to describe what the Bible says is our proclivity to battle something which God has already conquered. Listen to what this devotion in "None But The Hungry Heart" has to say about this subject: "The moment that you begin to fight with it (sin) —no matter how resolutely you may struggle against it—that moment is when you begin to experience sin as your master. For it is then that we forsake our true position, which is one of freedom from sin as a master."
"It is for freedom that Christ has set us free. Stand firm, then, and do not let yourselves be burdened again by a yoke of slavery." (Galatians 5:1)