God could have taken care of this already. God could have settled this question of good vs. evil and the devil’s free run could be over and done with. It’s not, but it could be.
Piper suggests one reason: That through the incremental defeat of Satan (instead of instantly and all-at-once) Jesus’ death plays the pivotal role. Its through Jesus’s death that Satan is defeated. And through Jesus’ death sin and the law have no power. That means that Satan is already defeated, even though he hasn’t left the field of battle.
So, God didn’t annihilate the Enemy – God defeated him and lets him live with his defeat.
One of the most insidious things that our Enemy does is to convince us that the outcome has yet to be determined. That there is still any doubt about the Victor. [Or barring that – that there is any battle at all.]
And that leaves us with an interesting choice. We still have a decision to make. We still have to choose which battle line to join. Our free will and the choices we make still matter and still have consequences. We still make meaningful decisions.
God desires your freely chosen allegiance. The Enemy desires to convince you that there is another, better Cause. Your choice, your fidelity matters.