I received the final installment in the Harry Potter film franchise this Christmas, and one morning last week I watched it whilst folding laundry. At this point, I don't even think I need to apologize or post "spoiler alerts," because if you've not seen or ready the Potter movies or books, frankly, it's your own fault!
So... as I watched the end of the entire saga, and Harry's final showdown with his bald, reptilian nemesis, I was struck by the defeat of Voldemort - as we should have been. Harry and friends have spent the last two (and a half) films, seeking out the horcruxes - those objects that contain pieces of the Dark Lord's soul - in order to destroy them and render the Evil One vulnerable. By the time Harry is able to impose his final wand blast against Voldemort, all seven of them have been destroyed; Voldemort is disarmed and then something interesting happens. Harry does not hit him again with his best shot. Rather, Voldy simply begins to fade away - fluttering off, bit by bit, like ashes into the wind. And he never saw it coming.
Cinematically, I am amazed at how much this resembled another defeat scene. It reminded me of the end of "The Passion of the Christ," as Jesus dies on the Cross and the soldiers flee in the face of the subsequent earthquake. There is a moment when we are shown the Satan figure, screaming and pained, as he/she realizes that Jesus has defeated him/her through the completion of His perfect sacrifice.
He never saw it coming.
There was no way that Evil could be defeated without evil being employed, was there? Therefore, the Devil could not recognize the perfect obedience by which Jesus' sacrifice of love destroyed sin and death and redeemed mankind.
Another similar death occurs at the end of The Matrix epic, as Neo finally confronts Agent Smith, alone in the world, surrounded by those whom Smith had conquered. Neo stops fighting, stops struggling, and he allows Smith to take him. In doing so, Smith is destroyed from within by the sacrifice of "the One." As he finally realizes that he has been defeated - not in the "usual" way, but through this sacrifice - he is incredulous. He is destroyed, as is his power over those others whom he had possessed. Another aerial shot shows the central defeat of Smith and a rippling out of that effect as each individual possessed is released.
The parallel here is Christ (well, not for the "Passion," since that was actually about Christ!). Harry first had to experience the death that Evil brings before he could liberate the world from its effects for good. Neo had to be absorbed by the power of evil before he could release others from that. This is what Saint Paul calls the "firstfruits of our redemption" or the "first-born of the dead." Jesus goes first, and His obedient sacrifice is the model upon which any Christian life and vocation is based - complete, self-less, submissive self-gift.
Why did not Harry use the ever-effective "avada kedavra" curse on Lord You-Know-Who? Because he didn't have to. If Harry had learned anything in his years at Hogwarts it's that love is the oldest and most effective magic there is. Voldemort never saw it coming.